JP2010081797A - Controller for system-interconnected power converting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely suppress the bias magnetism of a transformer which is caused by abnormality in a power system. <P>SOLUTION: In this controller for a system-interconnected power converting system, power conversion equipment 1, which has a power storage facility 7 and converts DC into AC or AC into DC, is connected in parallel with a load 8 of a power system, which has a power source 0, via a transformer 2, and the controller is equipped with a system-interconnecting switch 9, which can cut the load 8 and the power conversion equipment 1 off the power system, at a point of interconnecting with the power system. Usually, it stores power in the power storage facility 7 from the side of the power system, and discharges the power from the power storage facility 7, and in abnormal circumstances of the power system, it opens the system-interconnecting switch 9 so as to supply the load 8 with power from the power conversion equipment 1. The controller is equipped with a means which determines the output voltage of the power conversion equipment, limiting the magnitude of the output of only the axial component of either the axial component which accords with the component of the power voltage, or the axial component which crosses the axis at right angles, of a current controller on rotational coordinates which rotate synchronously with the power voltage of the power system, in the case where it is interconnected with the system, with the system-interconnecting switch ON. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a control device for a grid-connected power conversion system configured such that a power conversion device is linked to a power system having a power source via a transformer, and in particular, transformation caused by an abnormality such as a power system fault. The present invention relates to a control device for a grid-connected power conversion system that reliably suppresses the magnetic demagnetization and enhances system continuity.

  Conventionally, for example, when a DC power source such as a solar cell or a NaS battery is connected to a power system having a power source, it is necessary to convert the DC to AC by a power converter and connect it.

  In this case, in order to prevent voltage matching between the voltage of the power system and the DC power source that outputs the DC power, and the outflow of the DC component from the power converter, the power converter is provided with a transformer at its output stage. In many cases, a grid-connected power conversion system is configured in conjunction with a power system having a power source.

  While the power converter can output an arbitrary AC waveform, a DC component may be superimposed on the output due to a switching error or the influence of the power system, and the interconnection transformer may be demagnetized.

  Therefore, recently, a control device that suppresses and controls the magnetic bias of such a transformer has been proposed.

  FIG. 13 is a block diagram illustrating a configuration example of a control device of this type of conventional grid-connected power conversion system.

  In FIG. 13, a power conversion device 1 that converts direct current into alternating current or alternating current into direct current operates in conjunction with an electric power system having a power supply 0 via an interconnection transformer 2.

  The control device that suppresses and controls the demagnetization of the transformer 2 detects the DC component of the output voltage of the power converter 1 by the DC component detection circuit 3, and the DC component opposite to the DC component is detected by the demagnetization suppression circuit 4. The output power is superposed on the output of the control circuit 5 of the power converter 1, and the power converter 1 is controlled by the PWM pattern generation circuit 6.

  In FIG. 13, L indicates the system impedance of the power system.

  However, the control device for the conventional grid-connected power conversion system as described above has the following problems.

  That is, when detecting the direct current component of the output voltage of the power conversion device 1, it is necessary to detect the output voltage for at least one cycle, and thus it takes time to obtain the effect of the bias suppression control.

  Therefore, it is difficult to suppress the demagnetization phenomenon that occurs in a short time due to the power system abnormality or the like.

  Further, superimposing the DC component on the output terminal of the control circuit 5 of the power conversion device 1 is recognized as a disturbance when viewed from the control circuit 5.

  And since the control circuit 5 works so as to eliminate the influence of this disturbance, it may act to weaken the effect of the demagnetization suppression control, and the effect of the demagnetization suppression control is impaired.

  It is an object of the present invention to provide a control device for a grid-connected power conversion system that can reliably suppress transformer magnetic demagnetization caused by an abnormality such as a power system accident and improve the continuity of operation of the system. There is to do.

  In order to achieve the above object, a control device for a grid-connected power conversion system according to an aspect of the present invention provides a power conversion device that converts DC power output from a DC power source into AC power via a transformer. Connected to an electric power system having a power source and a load, and connected to the electric power system, the electric power system includes a grid interconnection switch capable of separating the load and the power converter from the electric power system. Compensation for power imbalance between the AC power output from the converter and the power system is performed, and when the power system is abnormal, the grid connection switch is opened to supply power to the load from the power converter. In the control device of the grid interconnection power conversion system, when the grid interconnection switch is opened and the grid interconnection is not established, in voltage control, the direct current generation of the output voltage of the power conversion device is performed. In order to suppress the power supply voltage of the power system, the change rate of the output of only one of the axis component that coincides with the power supply voltage component on the rotation coordinate that rotates synchronously or the axis component orthogonal to the axis Control means for limiting the size and determining the output voltage of the power converter is provided.

  According to the control device for the grid-connected power conversion system of the present invention, in the current controller on the rotating coordinate that rotates in synchronization with the power supply voltage of the power system when the grid-connected switch is turned on and the grid is linked. Whether to limit the magnitude of the output or input of only one of the axis component that matches the power supply voltage component or the axis component that is orthogonal to the axis, or the rate of change of the output Or, when the rate of change of the output exceeds the set value, limit the rate of change of the output and determine the output voltage of the power converter, or open the grid connection switch In the voltage controller on the rotating coordinate that rotates in synchronization with the power supply voltage of the power system when not connected to the grid, either the axis component that matches the power supply voltage component or the axis component that is orthogonal to the axis Only Limit the magnitude of the output or the rate of change of the output, or limit the magnitude of the rate of change of the output when the magnitude of the rate of change of the output exceeds the set value. Limit and determine the output voltage of the power converter, or when the grid connection switch is turned on and grid connection is detected, an abnormality in the power system is detected based on the predetermined amount of electricity in the system In this case, the current command to the current controller that controls the output current of the power conversion device is set to zero, so that it is possible to reliably suppress the magnet bias of the transformer caused by an abnormality such as a power system fault. Therefore, it becomes possible to improve the continuity of operation of the system.

The block diagram which shows 1st Embodiment of the control apparatus of the grid interconnection power conversion system by this invention. The block diagram which shows 2nd Embodiment of the control apparatus of the grid connection power conversion system by this invention. The block diagram which shows 3rd Embodiment of the control apparatus of the grid connection power conversion system by this invention. The block diagram which shows 4th Embodiment of the control apparatus of the grid connection power conversion system by this invention. The block diagram which shows 5th Embodiment of the control apparatus of the grid connection power conversion system by this invention. The block diagram which shows 6th Embodiment of the control apparatus of the grid connection power conversion system by this invention. The block diagram which shows 7th Embodiment of the control apparatus of the grid connection power conversion system by this invention. The block diagram which shows 8th Embodiment of the control apparatus of the grid interconnection power conversion system by this invention. The block diagram which shows 9th Embodiment of the control apparatus of the grid connection power conversion system by this invention. The block diagram which shows 10th Embodiment of the control apparatus of the grid connection power conversion system by this invention. The block diagram which shows 11th Embodiment of the control apparatus of the grid interconnection power conversion system by this invention. The block diagram which shows the schematic structural example of the power supply system which has a high-speed backup function. The block diagram which shows the structural example of the control apparatus of the conventional grid connection power conversion system.

  In the present invention, when the grid connection switch is turned on and the grid is linked, the axis component that coincides with the power supply voltage component or the axis in the current controller on the rotation coordinate that rotates synchronously with the power supply voltage of the power system Limit the size of the output or input of only one of the axis components orthogonal to the axis, or limit the magnitude of the rate of change of the output, or set the magnitude of the rate of change of the output When the value exceeds the value, limit the rate of change of the output and determine the output voltage of the power converter, or open the grid connection switch and the grid is not connected In the voltage controller on the rotating coordinate that rotates synchronously with the power supply voltage of the axis, the output or input size of only one of the axis component that coincides with the power supply voltage component or the axis component orthogonal to the axis is limited. Or Alternatively, the output voltage of the power converter is limited by limiting the magnitude of the output change rate or by limiting the output change rate when the output change rate exceeds a set value. If the power system abnormality is detected based on the predetermined amount of electricity in the system when the system connection switch is turned on or the system connection is turned on, the output current of the power converter is The voltage output from the power converter by detecting the power system abnormality quickly and continuing the unreasonable current control when the power system abnormality occurs by setting the current command to the current controller that controls the power to zero The increase in time product is suppressed, and the bias magnetism of the transformer is surely suppressed.

  Hereinafter, embodiments of the present invention based on the above-described concept will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram showing a configuration example of a control device for a grid-connected power conversion system according to the present embodiment, and the same elements as those in FIG.

  In FIG. 1, a power conversion device 1 having a power storage device 7 such as a secondary battery for storing power and converting direct current into alternating current or alternating current into direct current is connected to a power supply 0 via an interconnection transformer 2. Are connected in parallel to the power system and the load 8.

  Moreover, the grid connection switch 9 which can isolate | separate the load 8 and the power converter device 1 from this power grid is provided in the point linked with a power grid.

  Normally, power is stored in the power storage device 7 from the power system side or discharged from the power storage device 7, or reactive power compensation, harmonic compensation, or power imbalance compensation is performed. The system switch 9 is opened and power is supplied from the power converter 1 to the load 8.

  On the other hand, the control device includes a phase detection circuit 10, a stationary to rotation conversion circuit 11, a current command generation circuit 12, a controller 13, a limiting circuit 14, a rotation to stationary conversion circuit 15, and a PWM pattern generation circuit 6. And consists of

  The phase detection circuit 10 detects the phase of the power supply voltage of the power system.

  The stationary to rotation conversion circuit 11 uses the output from the phase detection circuit 10 to match the current output from the power conversion device 1 with the power supply voltage component on the dq rotation coordinate that rotates in synchronization with the power supply voltage of the power system. The current is converted into the current of the axis component to be converted and the current of the axis component orthogonal to the axis that matches the power supply voltage component.

  The current command generation circuit 12 generates a current command on dq rotation coordinates.

  The controller 13 generates an output such that the difference between the output from the stationary-to-rotation conversion circuit 11 and the output from the current command generation circuit 12 is zero.

  The limit circuit 14 outputs only one axis from the controller 13, that is, only one of the axis component that matches the power supply voltage component or the axis component orthogonal to the axis (in this example, the power supply voltage component). A modulated wave on the dq rotation coordinate is obtained by limiting the output magnitude of the axis component orthogonal to the axis that coincides with.

  The rotation-to-static conversion circuit 15 receives the output of the other axis from the controller 13 (in this example, the axis component that matches the power supply voltage component) and the output from the limiting circuit 14, and the phase detection circuit The output from 10 is converted into a voltage command on a stationary coordinate.

  The PWM pattern generation circuit 6 generates a gate pulse signal for controlling on / off of the self-extinguishing element of the power conversion device 1 based on the output from the rotation → stationary conversion circuit 15.

  In FIG. 1, L indicates the system impedance of the power system.

  Next, the operation of the control device for the grid-connected power conversion system according to the present embodiment configured as described above will be described.

  In FIG. 1, the power conversion apparatus 1 is connected to the power system via the transformer 2 by turning on the grid connection switch 9.

  When the grid connection switch 9 is turned on and connected to the grid, the power storage device 7 is charged and discharged from the power storage device 7, and thus operates as a control current source.

  The current output from the power conversion device 1 uses the output from the phase detection circuit 10 that detects the phase of the power supply voltage, and changes to a current on the dq rotation coordinate that rotates synchronously with the power supply voltage in the stationary to rotation conversion circuit 11. Converted.

Here, the direction of the power supply voltage on the dq rotation coordinates is made to coincide with the q axis.

  The value obtained by this conversion obtains a difference from the output from the current command generation circuit 12 on the dq rotation coordinates, and the controller 13 adjusts the output so that this difference becomes zero.

  As the controller 13, for example, a proportional controller, a proportional-integral controller, or a non-interference controller is used as necessary.

  Then, the limit circuit 14 limits the output of only one axis from the controller 13, that is, the output of the d axis here to limit the magnitude of the output, and the modulated wave on the dq rotation coordinates. Get.

The output of the other axis from the controller 13, that is, the output of the q axis here, and the output from the limiting circuit 14 are output on the stationary coordinates by the rotation-to-static conversion circuit 15 using the output from the phase detection circuit 10. Is converted to the voltage command.

  Based on the output from the rotation / stationary conversion circuit 15, the PWM pattern generation circuit 6 generates a gate pulse signal for controlling on / off of the self-extinguishing element of the power conversion device 1.

  In this way, by determining the output voltage of the power conversion device 1 and suppressing a sudden change in the d-axis modulated wave, it is possible to suppress an increase in the voltage-time product output by the power conversion device 1. .

  In the present embodiment, a case has been described in which the output of one axis from the controller 13, that is, the output of the d axis is limited to limit the size of the output. The output of only the other axis from 13, that is, the output of the q axis may be limited to limit the magnitude of the output. In this case, a sudden change in the modulated wave of the q axis is suppressed. By doing, it can suppress that the voltage time product which the power converter device 1 outputs increases.

  As described above, in the control device for the grid interconnection power conversion system according to the present embodiment, when the grid interconnection switch 9 is turned on and grid interconnection is performed, the d− rotates in synchronization with the power supply voltage of the power grid. In the current controller on the q rotation coordinate, the output of the power conversion device 1 is limited by limiting the output magnitude of only one of the axis component coinciding with the power supply voltage component or the axis component orthogonal to the axis. Since the voltage is determined, the increase in the voltage time product of the output voltage of the power conversion device 1 can be limited, so that the bias of the transformer 2 can be reliably suppressed, and the continuity of operation of the system is improved. It becomes possible.

(Second Embodiment)
FIG. 2 is a block diagram showing a configuration example of the control device of the grid-connected power conversion system according to the present embodiment. The same parts as those in FIG. Only the part is described.

  That is, the control device for the grid-connected power conversion system according to the present embodiment has a configuration in which the limiting circuit 14 in FIG. 1 is provided in the input stage of the controller 13 as shown in FIG.

  The limit circuit 14 inputs only one of the axes to the controller 13, that is, only one of the axis component that coincides with the power supply voltage component or the axis component that is orthogonal to the axis (in this example, the power supply voltage component). The input component of the axis component orthogonal to the axis that coincides with () is limited to obtain a modulated wave on dq rotation coordinates.

  The rotation-to-stationary conversion circuit 15 inputs the output of one axis from the controller 13 and the output of the other axis, and converts it into a voltage command on the stationary coordinates using the output from the phase detection circuit 10. .

  Next, the operation of the control device for the grid-connected power conversion system according to the present embodiment configured as described above will be described.

  The description of the operation of the same part as in FIG. 1 is omitted, and only the operation of the different part will be described here.

  In FIG. 2, the value obtained by the conversion in the stationary → rotation conversion circuit 11 obtains a difference from the output from the current command generation circuit 12 on the dq rotation coordinate, and the controller 13 sets this difference to zero. Adjust the output so that

  Here, the limit circuit 14 limits the input of only one axis to the controller 13, that is, the d-axis input here to limit the size of the input, and modulates on the dq rotation coordinate. Get the waves.

  The output of one axis from the controller 13, that is, the output of the d axis here, and the output of the other axis, that is, the output of the q axis here, are converted from rotation to stationary using the output from the phase detection circuit 10. The circuit 15 converts it into a voltage command on a stationary coordinate.

  Based on the output from the rotation / stationary conversion circuit 15, the PWM pattern generation circuit 6 generates a gate pulse signal for controlling on / off of the self-extinguishing element of the power conversion device 1.

  In this way, by determining the output voltage of the power conversion device 1 and suppressing a sudden change in the d-axis modulated wave, it is possible to suppress an increase in the voltage-time product output by the power conversion device 1. .

  In the present embodiment, a case has been described in which the input of one axis to the controller 13, that is, the input of the d axis is limited to limit the size of the input. The input of only the other axis to 13, that is, the input of the q axis may be limited to limit the magnitude of the input. In this case, a sudden change in the modulated wave of the q axis is suppressed. By doing, it can suppress that the voltage time product which the power converter device 1 outputs increases.

  As described above, in the control device for the grid interconnection power conversion system according to the present embodiment, when the grid interconnection switch 9 is turned on and grid interconnection is performed, the d− rotates in synchronization with the power supply voltage of the power grid. In the current controller on the q rotation coordinate, the output of the power conversion device 1 is limited by limiting the input magnitude of only one of the axis component that coincides with the power supply voltage component or the axis component that is orthogonal to the axis. Since the voltage is determined, the increase in the voltage time product of the output voltage of the power conversion device 1 can be limited, so that the bias of the transformer 2 can be reliably suppressed, and the continuity of operation of the system is improved. It becomes possible.

(Third embodiment)
FIG. 3 is a block diagram showing a configuration example of the control device of the grid-connected power conversion system according to the present embodiment. The same parts as those in FIG. Only the part is described.

  That is, as shown in FIG. 3, the control device for the grid-connected power conversion system according to the present embodiment omits the limiting circuit 14 in FIG. 1 and includes a change rate limiting circuit 16 instead. It is said.

  The rate-of-change limiting circuit 16 outputs only one axis from the controller 13, that is, only one of the axis component that coincides with the power supply voltage component or the axis component that is orthogonal to the axis (in this example, the power supply By limiting the magnitude of the rate of change of the output of the axis component orthogonal to the axis that matches the voltage component, a modulated wave on the dq rotation coordinate is obtained.

  Next, the operation of the control device for the grid-connected power conversion system according to the present embodiment configured as described above will be described.

  The description of the operation of the same part as in FIG. 1 is omitted, and only the operation of the different part will be described here.

  In FIG. 3, the value obtained by the conversion from the stationary to rotation conversion circuit 11 obtains a difference from the output from the current command generation circuit 12 on the dq rotation coordinate, and the controller 13 sets this difference to zero. Adjust the output so that

  Then, the change rate limiting circuit 16 limits the output rate of only one axis from the controller 13, that is, the change rate of the d-axis output here, and limits the change rate of the output. Then, a modulated wave on the dq rotation coordinate is obtained.

  The output of the other axis from the controller 13, that is, the output of the q-axis here and the output from the change rate limiting circuit 16 are stationary in the rotation-to-static conversion circuit 15 using the output from the phase detection circuit 10. Convert to voltage command on coordinates.

  Based on the output from the rotation / stationary conversion circuit 15, the PWM pattern generation circuit 6 generates a gate pulse signal for controlling on / off of the self-extinguishing element of the power conversion device 1.

  In this way, by determining the output voltage of the power conversion device 1 and suppressing a sudden change in the d-axis modulated wave, it is possible to suppress an increase in the voltage-time product output by the power conversion device 1. .

  In the present embodiment, a case has been described in which the change rate of the output of one axis from the controller 13, that is, the d-axis is limited to limit the change rate of the output. Not limited to this, the output of only the other axis from the controller 13, that is, the change rate of the output of the q axis may be limited to limit the magnitude of the change rate of the output. By suppressing a sudden change in the q-axis modulated wave, it is possible to suppress an increase in the voltage time product output from the power conversion device 1.

  As described above, in the control device for the grid interconnection power conversion system according to the present embodiment, when the grid interconnection switch 9 is turned on and grid interconnection is performed, the d− rotates in synchronization with the power supply voltage of the power grid. In the current controller on the q rotation coordinate, the power conversion device limits the magnitude of the output change rate of only one of the axis component that coincides with the power supply voltage component or the axis component that is orthogonal to the axis. Since the output voltage of 1 is determined, the increase in the voltage-time product of the output voltage of the power converter 1 can be limited, and the bias of the transformer 2 can be reliably suppressed, and the system operation can be continued. It becomes possible to improve the nature.

(Fourth embodiment)
FIG. 4 is a block diagram showing a configuration example of the control device of the grid-connected power conversion system according to the present embodiment. The same parts as those in FIG. Only the part is described.

  That is, as shown in FIG. 4, the control device for the grid-connected power conversion system according to the present embodiment omits the limiting circuit 14 in FIG. 1, and replaces it with a change rate limiting circuit 17 with an allowable value. It has a configuration with.

  The change rate limiting circuit with tolerance value 17 outputs only one axis component from the controller 13, that is, one of the axis component that coincides with the power supply voltage component or the axis component orthogonal to the axis (this example) Then, if it is detected that the magnitude of the output change rate of the output of the axis component orthogonal to the axis that matches the power supply voltage component exceeds the allowable value, the magnitude of the output change rate is limited, and d−q Get the modulated wave on the rotating coordinates.

  Next, the operation of the control device for the grid-connected power conversion system according to the present embodiment configured as described above will be described.

  The description of the operation of the same part as in FIG. 1 is omitted, and only the operation of the different part will be described here.

  In FIG. 4, the value obtained by the conversion in the stationary-to-rotation conversion circuit 11 obtains a difference from the output from the current command generation circuit 12 on the dq rotation coordinate, and the controller 13 sets this difference to zero. Adjust the output so that

  Then, the change rate limiting circuit 17 with allowable value outputs the input as it is when the output of only one axis from the controller 13, that is, the change rate of the output of the d axis here is within the allowable value. However, when the allowable value is exceeded, the magnitude of the change rate of the output of the d axis is limited to limit the magnitude of the change rate of the output, and a modulated wave on the dq rotation coordinate is obtained.

  The output of the other axis from the controller 13, that is, the output of the q-axis here and the output from the change rate limiting circuit 17 with allowable value are output from the phase detection circuit 10 using the rotation-to-static conversion circuit 15. To convert to a voltage command on stationary coordinates.

  Based on the output from the rotation / stationary conversion circuit 15, the PWM pattern generation circuit 6 generates a gate pulse signal for controlling on / off of the self-extinguishing element of the power conversion device 1.

  In this way, by determining the output voltage of the power conversion device 1 and suppressing a sudden change in the d-axis modulated wave, it is possible to suppress an increase in the voltage-time product output by the power conversion device 1. .

  In this embodiment, when it is detected that the change rate of the output of one axis from the controller 13, that is, the d-axis exceeds the allowable value, the limit of the change rate of the output is limited. However, the present invention is not limited to this, and the output of only the other axis from the controller 13, that is, the magnitude of the change rate of the q-axis output is not limited. When it is detected that the allowable value is exceeded, the magnitude of the change rate of the output may be limited to limit the magnitude of the change rate of the output. By suppressing the rapid change in the voltage, it is possible to suppress an increase in the voltage time product output from the power conversion device 1.

  As described above, in the control device for the grid interconnection power conversion system according to the present embodiment, when the grid interconnection switch 9 is turned on and grid interconnection is performed, the d− rotates in synchronization with the power supply voltage of the power grid. In the current controller on the q rotation coordinate, the magnitude of the rate of change of the output of only one of the axis component that coincides with the power supply voltage component or the axis component that is orthogonal to the axis exceeds the allowable value. When detected, the output voltage of the power conversion device 1 is determined by limiting the magnitude of the rate of change of the output, so the increase in the voltage time product of the output voltage of the power conversion device 1 is limited, The bias magnetism of the transformer 2 can be reliably suppressed, and the continuity of operation of the system can be improved.

(Fifth embodiment)
FIG. 5 is a block diagram showing a configuration example of the control device of the grid-connected power conversion system according to the present embodiment. The same elements as those in FIG. Only the part is described.

  In FIG. 5, the control device includes a phase detection circuit 10, a stationary to rotation conversion circuit 11, a voltage command generation circuit 18, a controller 13, a limiting circuit 14, a rotation to stationary conversion circuit 15, and a PWM pattern generation. The circuit 6 is constituted.

  The phase detection circuit 10 detects the phase of the power supply voltage of the power system.

  The stationary-to-rotation conversion circuit 11 uses the output from the phase detection circuit 10 to match the voltage output from the power conversion device 1 with the power supply voltage component on the dq rotation coordinate that rotates in synchronization with the power supply voltage of the power system. To the voltage of the axis component orthogonal to the axis that matches the power supply voltage component.

  The voltage command generation circuit 18 generates a voltage command on dq rotation coordinates.

  The controller 13 generates an output that makes the difference between the output from the stationary-to-rotation conversion circuit 11 and the output from the voltage command generation circuit 18 zero.

  The limit circuit 14 outputs only one axis from the controller 13, that is, only one of the axis component that matches the power supply voltage component or the axis component orthogonal to the axis (in this example, the power supply voltage component). A modulated wave on the dq rotation coordinate is obtained by limiting the output magnitude of the axis component orthogonal to the axis that coincides with.

  The rotation-to-static conversion circuit 15 receives the output of the other axis from the controller 13 (in this example, the axis component that matches the power supply voltage component) and the output from the limiting circuit 14, and the phase detection circuit The output from 10 is converted into a voltage command on a stationary coordinate.

  The PWM pattern generation circuit 6 generates a gate pulse signal for controlling on / off of the self-extinguishing element of the power conversion device 1 based on the output from the rotation → stationary conversion circuit 15.

  Next, the operation of the control device for the grid-connected power conversion system according to the present embodiment configured as described above will be described.

  In FIG. 5, the power conversion apparatus 1 is connected to the power system via the transformer 2 by turning on the grid connection switch 9.

  When the grid connection switch 9 is turned on and connected to the grid, the power storage device 7 is charged and discharged from the power storage device 7, and thus operates as a control voltage source.

  The voltage output from the power conversion device 1 uses the output from the phase detection circuit 10 that detects the phase of the power supply voltage, and changes to a voltage on the dq rotation coordinate that rotates synchronously with the power supply voltage in the stationary to rotation conversion circuit 11. Converted.

  Here, the direction of the power supply voltage on the dq rotation coordinates is made to coincide with the q axis.

  The value obtained by this conversion obtains a difference from the output from the voltage command generation circuit 18 on the dq rotation coordinates, and the controller 13 adjusts the output so that this difference becomes zero.

  As the controller 13, for example, a proportional controller, a proportional-integral controller, or a non-interference controller is used as necessary.

  Then, the limit circuit 14 limits the output of only one axis from the controller 13, that is, the output of the d axis here to limit the magnitude of the output, and the modulated wave on the dq rotation coordinates. Get.

  The output of the other axis from the controller 13, that is, the output of the q axis here, and the output from the limiting circuit 14 are output on the stationary coordinate by the rotation → stationary conversion circuit 15 using the output from the phase detection circuit 10. Is converted to the voltage command.

  Based on the output from the rotation / stationary conversion circuit 15, the PWM pattern generation circuit 6 generates a gate pulse signal for controlling on / off of the self-extinguishing element of the power conversion device 1.

  In this way, by determining the output voltage of the power conversion device 1 and suppressing a sudden change in the d-axis modulated wave, it is possible to suppress an increase in the voltage-time product output by the power conversion device 1. .

  In the present embodiment, a case has been described in which the output of one axis from the controller 13, that is, the output of the d axis is limited to limit the size of the output. The output of only the other axis from 13, that is, the output of the q axis may be limited to limit the magnitude of the output. In this case, a sudden change in the modulated wave of the q axis is suppressed. By doing, it can suppress that the voltage time product which the power converter device 1 outputs increases.

  As described above, in the control device for the grid interconnection power conversion system according to the present embodiment, when the grid interconnection switch 9 is turned on and the grid interconnection is not established, the d− rotates in synchronization with the power supply voltage of the power grid. In the voltage controller on the q rotation coordinate, the output voltage of the power converter 1 is limited by limiting the output magnitude of only one of the axis component that coincides with the power supply voltage component or the axis component that is orthogonal to the axis. Therefore, the increase in the voltage time product of the output voltage of the power conversion device 1 can be limited to reliably suppress the magnetization of the transformer 2 and improve the continuity of operation of the system. Is possible.

(Sixth embodiment)
FIG. 6 is a block diagram showing a configuration example of the control device of the grid-connected power conversion system according to the present embodiment. The same parts as those in FIG. Only the part is described.

  That is, the control apparatus for the grid-connected power conversion system according to the present embodiment has a configuration in which the limiting circuit 14 in FIG. 5 is provided in the input stage of the controller 13 as shown in FIG.

  The limit circuit 14 inputs only one of the axes to the controller 13, that is, only one of the axis component that coincides with the power supply voltage component or the axis component that is orthogonal to the axis (in this example, the power supply voltage component). The input component of the axis component orthogonal to the axis that coincides with () is limited to obtain a modulated wave on dq rotation coordinates.

  The rotation-to-stationary conversion circuit 15 inputs the output of one axis from the controller 13 and the output of the other axis, and converts it into a voltage command on the stationary coordinates using the output from the phase detection circuit 10. .

  Next, the operation of the control device for the grid-connected power conversion system according to the present embodiment configured as described above will be described.

  The description of the operation of the same part as in FIG. 5 is omitted, and only the operation of the different part will be described here.

  In FIG. 6, the value obtained by the conversion in the stationary → rotation conversion circuit 11 obtains a difference from the output from the voltage command generation circuit 18 on the dq rotation coordinates, and the controller 13 sets this difference to zero. Adjust the output so that

  Here, the limit circuit 14 limits the input of only one axis to the controller 13, that is, the d-axis input here to limit the size of the input, and modulates on the dq rotation coordinate. Get the waves.

  The output of one axis from the controller 13, that is, the output of the d axis here, and the output of the other axis, that is, the output of the q axis here, are converted from rotation to stationary using the output from the phase detection circuit 10. The circuit 15 converts it into a voltage command on a stationary coordinate.

  Based on the output from the rotation / stationary conversion circuit 15, the PWM pattern generation circuit 6 generates a gate pulse signal for controlling on / off of the self-extinguishing element of the power conversion device 1.

  In this way, by determining the output voltage of the power conversion device 1 and suppressing a sudden change in the d-axis modulated wave, it is possible to suppress an increase in the voltage-time product output by the power conversion device 1. .

  In the present embodiment, a case has been described in which the input of one axis to the controller 13, that is, the input of the d axis is limited to limit the size of the input. The input of only the other axis to 13, that is, the input of the q axis may be limited to limit the magnitude of the input. In this case, a sudden change in the modulated wave of the q axis is suppressed. By doing, it can suppress that the voltage time product which the power converter device 1 outputs increases.

  As described above, in the control device for the grid interconnection power conversion system according to the present embodiment, when the grid interconnection switch 9 is turned on and the grid interconnection is not established, the d− rotates in synchronization with the power supply voltage of the power grid. In the voltage controller on the q rotation coordinate, the output of the power conversion device 1 is limited by limiting the input magnitude of only one of the axis component that coincides with the power supply voltage component or the axis component that is orthogonal to the axis. Since the voltage is determined, the increase in the voltage time product of the output voltage of the power conversion device 1 can be limited, so that the bias of the transformer 2 can be reliably suppressed, and the continuity of operation of the system is improved. It becomes possible.

(Seventh embodiment)
FIG. 7 is a block diagram showing a configuration example of the control device of the grid-connected power conversion system according to the present embodiment. The same parts as those in FIG. Only the part is described.

  That is, the control device for the grid-connected power conversion system according to the present embodiment has a configuration in which, as shown in FIG. 7, the limiting circuit 14 in FIG. 5 is omitted, and a change rate limiting circuit 16 is provided instead. It is said.

  The rate-of-change limiting circuit 16 outputs only one axis from the controller 13, that is, only one of the axis component that coincides with the power supply voltage component or the axis component that is orthogonal to the axis (in this example, the power supply By limiting the magnitude of the rate of change of the output of the axis component orthogonal to the axis that matches the voltage component, a modulated wave on the dq rotation coordinate is obtained.

  Next, the operation of the control device for the grid-connected power conversion system according to the present embodiment configured as described above will be described.

  The description of the operation of the same part as in FIG. 5 is omitted, and only the operation of the different part will be described here.

  In FIG. 7, the value obtained by the conversion from the stationary to rotation conversion circuit 11 obtains a difference from the output from the voltage command generation circuit 18 on the dq rotation coordinates, and the controller 13 sets this difference to zero. Adjust the output so that

  Then, the change rate limiting circuit 16 limits the output rate of only one axis from the controller 13, that is, the change rate of the d-axis output here, and limits the change rate of the output. Then, a modulated wave on the dq rotation coordinate is obtained.

  The output of the other axis from the controller 13, that is, the output of the q-axis here and the output from the change rate limiting circuit 16 are stationary in the rotation-to-static conversion circuit 15 using the output from the phase detection circuit 10. Convert to voltage command on coordinates.

  Based on the output from the rotation / stationary conversion circuit 15, the PWM pattern generation circuit 6 generates a gate pulse signal for controlling on / off of the self-extinguishing element of the power conversion device 1.

  In this way, by determining the output voltage of the power conversion device 1 and suppressing a sudden change in the d-axis modulated wave, it is possible to suppress an increase in the voltage-time product output by the power conversion device 1. .

  In the present embodiment, a case has been described in which the change rate of the output of one axis from the controller 13, that is, the d-axis is limited to limit the change rate of the output. Not limited to this, the output of only the other axis from the controller 13, that is, the change rate of the output of the q axis may be limited to limit the magnitude of the change rate of the output. By suppressing a sudden change in the q-axis modulated wave, it is possible to suppress an increase in the voltage time product output from the power conversion device 1.

  As described above, in the control device for the grid interconnection power conversion system according to the present embodiment, when the grid interconnection switch 9 is turned on and the grid interconnection is not established, the d− rotates in synchronization with the power supply voltage of the power grid. In the voltage controller on the q rotation coordinate, the power conversion device limits the magnitude of the rate of change of the output of only one of the axis component coinciding with the power supply voltage component or the axis component orthogonal to the axis. Since the output voltage of 1 is determined, the increase in the voltage-time product of the output voltage of the power converter 1 can be limited, and the bias of the transformer 2 can be reliably suppressed, and the system operation can be continued. It becomes possible to improve the nature.

(Eighth embodiment)
FIG. 8 is a block diagram showing a configuration example of the control device of the grid-connected power conversion system according to the present embodiment. The same parts as those in FIG. Only the part is described.

  That is, as shown in FIG. 8, the control device for the grid-connected power conversion system according to the present embodiment omits the limiting circuit 14 in FIG. 5 and replaces it with a change rate limiting circuit 17 with an allowable value. It has a configuration with.

  The change rate limiting circuit with tolerance value 17 outputs only one axis component from the controller 13, that is, one of the axis component that coincides with the power supply voltage component or the axis component orthogonal to the axis (this example) Then, if it is detected that the magnitude of the output change rate of the output of the axis component orthogonal to the axis that matches the power supply voltage component exceeds the allowable value, the magnitude of the output change rate is limited, and d−q Get the modulated wave on the rotating coordinates.

  Next, the operation of the control device for the grid-connected power conversion system according to the present embodiment configured as described above will be described.

  The description of the operation of the same part as in FIG. 5 is omitted, and only the operation of the different part will be described here.

  In FIG. 8, the value obtained by the conversion from the stationary to rotation conversion circuit 11 is obtained as a difference from the output from the voltage command generation circuit 18 on the dq rotation coordinates, and this difference is reduced to zero by the controller 13. Adjust the output so that

  Then, the change rate limiting circuit 17 with allowable value outputs the input as it is when the output of only one axis from the controller 13, that is, the change rate of the output of the d axis here is within the allowable value. However, when the allowable value is exceeded, the magnitude of the change rate of the output of the d axis is limited to limit the magnitude of the change rate of the output, and a modulated wave on the dq rotation coordinate is obtained.

  The output of the other axis from the controller 13, that is, the output of the q-axis here and the output from the change rate limiting circuit 17 with allowable value are output from the phase detection circuit 10 using the rotation-to-static conversion circuit 15. To convert to a voltage command on stationary coordinates.

  Based on the output from the rotation / stationary conversion circuit 15, the PWM pattern generation circuit 6 generates a gate pulse signal for controlling on / off of the self-extinguishing element of the power conversion device 1.

  In this way, by determining the output voltage of the power conversion device 1 and suppressing a sudden change in the d-axis modulated wave, it is possible to suppress an increase in the voltage-time product output by the power conversion device 1. .

  In this embodiment, when it is detected that the change rate of the output of one axis from the controller 13, that is, the d-axis exceeds the allowable value, the limit of the change rate of the output is limited. However, the present invention is not limited to this, and the output of only the other axis from the controller 13, that is, the magnitude of the change rate of the q-axis output is not limited. When it is detected that the allowable value is exceeded, the magnitude of the change rate of the output may be limited to limit the magnitude of the change rate of the output. By suppressing the rapid change in the voltage, it is possible to suppress an increase in the voltage time product output from the power conversion device 1.

  As described above, in the control device for the grid interconnection power conversion system according to the present embodiment, when the grid interconnection switch 9 is turned on and the grid interconnection is not established, the d− rotates in synchronization with the power supply voltage of the power grid. In the voltage controller on the q rotation coordinate, the magnitude of the rate of change of the output of only one of the axis component coincident with the power supply voltage component or the axis component orthogonal to the axis exceeds the allowable value. When detected, the output voltage of the power conversion device 1 is determined by limiting the magnitude of the rate of change of the output, so the increase in the voltage time product of the output voltage of the power conversion device 1 is limited, The bias magnetism of the transformer 2 can be reliably suppressed, and the continuity of operation of the system can be improved.

(Ninth embodiment)
FIG. 9 is a block diagram illustrating a configuration example of the control device of the grid-connected power conversion system according to the present embodiment. The same components as those in FIG. Only the part is described.

  In FIG. 9, the control device includes a phase detection circuit 10, a stationary to rotation conversion circuit 11, a voltage decrease detection circuit 19, a current command nulling circuit 20, and a current command generation circuit 12.

  The phase detection circuit 10 detects the phase of the power supply voltage of the power system.

  The stationary-to-rotation conversion circuit 11 uses the output from the phase detection circuit 10 to match the power supply voltage of the power system with the power supply voltage component on the dq rotation coordinate that rotates in synchronization with the power supply voltage of the power system. And the voltage of the axis component orthogonal to the axis that coincides with the power supply voltage component.

  The voltage decrease detection circuit 19 receives, as an input, the voltage of the axis component that matches the power supply voltage component among the outputs from the stationary to rotation conversion circuit 11, and detects that the voltage decrease is equal to or greater than a set value.

  The current command zeroing circuit 20 receives the output from the voltage decrease detection circuit 19, and when it is detected that the voltage decrease is greater than or equal to a set value, it determines that the power system is abnormal and determines the current command generation circuit. The current command generated from 12 is set to zero.

  Next, the operation of the control device for the grid-connected power conversion system according to the present embodiment configured as described above will be described.

  In FIG. 9, the power conversion device 1 is connected to the power system via the transformer 2 by turning on the grid connection switch 9.

  When the grid connection switch 9 is turned on and connected to the grid, the power storage device 7 is charged and discharged from the power storage device 7, and thus operates as a control current source.

  When any abnormality occurs in the power system, the grid connection switch 9 is opened and power is supplied from the power converter 1 to the load 8.

  The power supply voltage of the power system is converted into a voltage on the dq rotation coordinate that rotates in synchronization with the power supply voltage by the stationary-to-rotation conversion circuit 11 using the output from the phase detection circuit 10 that detects the phase of the power supply voltage. .

  Here, the direction of the power supply voltage on the dq rotation coordinates is made to coincide with the q axis.

  Therefore, when the power system is normal, only the q-axis component has a value and the d-axis component is not detected.

  On the other hand, when any abnormality occurs in the power system, the q-axis voltage component Vq decreases rapidly.

  When this decrease is detected by the voltage decrease detection circuit 19 and it is detected that the voltage decrease value is greater than or equal to the set value, it is determined that the power system is abnormal, and the current command generation circuit 12 is determined by the current command zeroing circuit 20. Is forcibly made zero, and the output current of the power converter 1 is made zero.

  As described above, in the control apparatus for the grid interconnection power conversion system according to the present embodiment, when the grid interconnection switch 9 is turned on and the grid interconnection is performed, the rotation coordinates that rotate synchronously with the power supply voltage of the power grid By detecting that the decrease in the axis component that matches the power supply voltage component above is greater than or equal to the set value, it is determined that the power system is abnormal and the output current command of the power converter 1 is made zero. Therefore, the increase in the voltage time product output from the power converter 1 can be suppressed by quickly detecting the power system abnormality and continuing the unreasonable current control at the time of the power system abnormality. It is possible to reliably suppress the magnetic bias of the transformer 2 caused by continuing the operation, and to improve the continuity of operation of the system.

(Tenth embodiment)
FIG. 10 is a block diagram illustrating a configuration example of the control device for the grid-connected power conversion system according to the present embodiment. The same parts as those in FIG. 9 are denoted by the same reference numerals, and the description thereof is omitted. Only the part is described.

  That is, as shown in FIG. 10, the control device for the grid-connected power conversion system according to the present embodiment omits the voltage decrease detection circuit 19 in FIG. 9, and instead of this, the voltage increase detection circuit 21. It is set as the structure provided with.

  The voltage increase detection circuit 21 receives, as an input, the voltage of the axis component orthogonal to the axis that coincides with the power supply voltage component of the output from the stationary to rotation conversion circuit 11, and the increase in the voltage is greater than or equal to the set value. Is detected.

  The current command zeroing circuit 20 receives the output from the voltage increase detection circuit 21, and when it is detected that the voltage increase is equal to or greater than a set value, it determines that the power system is abnormal and determines the current command generation circuit. The current command generated from 12 is set to zero.

  Next, the operation of the control device for the grid-connected power conversion system according to the present embodiment configured as described above will be described.

  The description of the operation of the same part as in FIG. 9 is omitted, and only the operation of the different part will be described here.

  In FIG. 10, when the grid connection is performed by turning on the grid connection switch 8, the power supply voltage component of the power system has only the q-axis voltage component Vq, and the d-axis voltage component Vd is not detected.

  When any abnormality occurs in the power system, the d-axis voltage component Vd increases rapidly.

  When this increase is detected by the voltage increase detection circuit 14 and it is detected that the voltage increase value is greater than or equal to the set value, it is determined that the power system is abnormal, and the current command generating circuit 12 is determined by the current command zeroing circuit 20. Is forcibly made zero, and the output current of the power converter 1 is made zero.

  As described above, in the control apparatus for the grid interconnection power conversion system according to the present embodiment, when the grid interconnection switch 9 is turned on and the grid interconnection is performed, the rotation coordinates that rotate synchronously with the power supply voltage of the power grid By detecting that the increment of the axis component orthogonal to the axis that coincides with the upper power supply voltage component is greater than or equal to the set value, it is determined that the power system is abnormal and the output current command of the power converter 1 is made zero. As a result, an increase in the voltage time product output from the power conversion device 1 can be suppressed by quickly detecting a power system abnormality and continuing an unreasonable current control at the time of the power system abnormality. It is possible to reliably suppress the bias of the transformer 2 caused by continuing the current control at the time of abnormality, and it is possible to improve the operation continuity of the system.

(Eleventh embodiment)
FIG. 11 is a block diagram illustrating a configuration example of the control device of the grid-connected power conversion system according to the present embodiment. The same parts as those in FIG. 9 are denoted by the same reference numerals, and the description thereof is omitted. Only the part is described.

  That is, as shown in FIG. 11, the control device for the grid-connected power conversion system according to the present embodiment omits the stationary-to-rotation conversion circuit 11 and the voltage decrease detection circuit 19 in FIG. The change rate detection circuit 22 is provided.

  The change rate detection circuit 22 receives the output from the phase detection circuit 10 and detects that the magnitude of the change rate of the detected phase exceeds the limit value.

  The current command zeroing circuit 20 receives the output from the rate-of-change detection circuit 22 and, when detecting that the magnitude of the rate of change of the detection phase exceeds the limit value, determines that the power system is abnormal and determines the current. The current command generated from the command generation circuit 12 is set to zero.

  Next, the operation of the control device for the grid-connected power conversion system according to the present embodiment configured as described above will be described.

  The description of the operation of the same part as in FIG. 9 is omitted, and only the operation of the different part will be described here.

  In FIG. 11, the phase of the interconnection point voltage is detected by the phase detection circuit 10 in the steady state when the grid interconnection switch 8 is turned on.

  When any abnormality occurs in the power system, the detection phase changes abruptly.

  When this change is detected by the change rate detection circuit 15 and it is detected that the magnitude of the change rate of the detected phase exceeds the limit value, it is determined that the power system is abnormal, and the current command zeroing circuit 20 The current command from the command generation circuit 12 is forcibly set to zero, and the output current of the power converter 1 is set to zero.

  As described above, in the control device for the grid interconnection power conversion system according to the present embodiment, when the grid interconnection switch 8 is turned on and the grid interconnection is performed, the phase of the power supply voltage of the power grid is detected. By detecting that the magnitude of the rate of change exceeds the limit value, it is determined that the power system is abnormal and the output current command of the power converter 1 is set to zero. The increase in the voltage time product output from the power conversion device 1 can be suppressed by detecting the current in an abnormal state and continuing the unreasonable current control when the power system is abnormal, and the transformer generated by continuing the current control when the power system is abnormal 2 can be reliably suppressed, and the continuity of operation of the system can be improved.

(Other embodiments)
FIG. 12 is a block diagram illustrating a schematic configuration example of a power supply system having a high-speed backup function, and the same components as those in FIGS. 1 to 11 are denoted by the same reference numerals.

  That is, as shown in FIG. 12, the power supply system according to the present embodiment is provided in the power conversion device 1 and the grid connection switch 8 that can disconnect the load 8 and the power conversion device 1 from the power system having the power source. A power storage device 7 such as a secondary battery for storing power, a transformer 2 for connecting the output of the power conversion device 1 to the power supply voltage of the power system, and the voltage at the connection point of the power system The voltage detector 23 to detect, the phase detector 10 to detect the voltage phase of the interconnection point of the power system, the voltage detector 24 to detect the output voltage of the power converter 1, and the output current of the power converter 1 A current detector 25 to detect, a voltage control circuit 26 for controlling the output voltage of the power conversion device 1, a current control circuit 27 for controlling the output current of the power conversion device 1, and an abnormality in the power system to detect grid connection Open / throw switch 9 A system abnormality determination circuit 28 constitutes a switching circuit 29 for switching between current control and voltage control according to the state of the power system.

  By applying any one of the first to eleventh embodiments to the power conversion system that constitutes the power supply system having such a high-speed backup function, the present system is similar to the above case. It is possible to obtain an operational effect.

  In the figure, the case of a three-phase system is shown, but the configuration is not limited to this, and the configuration is substantially the same for a single-phase system.

  DESCRIPTION OF SYMBOLS 0 ... Power supply, 1 ... Power converter device, 2 ... Transformer, 3 ... DC component detection circuit, 4 ... Demagnetization suppression circuit, 5 ... Control circuit of power converter device, 6 ... PWM pattern generation circuit, 7 ... Power storage device , 8, load, 9, grid connection switch, 10, phase detection circuit, 11, stationary to rotation conversion circuit, 12, current command generation circuit, 13, controller, 14, limiting circuit, 15, rotation to stationary conversion circuit 16 ... Change rate limiting circuit, 17 ... Change rate limiting circuit with allowable value, 18 ... Voltage command generation circuit, 19 ... Voltage decrease detection circuit, 20 ... Current command zeroing circuit, 21 ... Voltage increase detection circuit, 22 ... change rate detection circuit, 23 ... voltage detector, 24 ... voltage detector, 25 ... current detector, 26 ... voltage control circuit, 27 ... current control circuit, 28 ... system abnormality determination circuit 29 ... switching circuit.

Claims (2)

A power conversion device that converts DC power output from a DC power source into AC power is connected to a power system having a power source and a load via a transformer, and connected to the power system from the power system. Provided with a grid interconnection switch capable of disconnecting the load and the power converter, and always performing power imbalance compensation between the AC power output from the power converter and the power system, and when the power system is abnormal In the control device of the grid interconnection power conversion system that opens the grid interconnection switch and supplies power to the load from the power conversion device.
Rotation coordinates that rotate synchronously with the power supply voltage of the power system in order to suppress the DC component of the output voltage of the power converter in voltage control when the system connection switch is opened and not connected to the system Control for determining the output voltage of the power conversion device by limiting the magnitude of the rate of change of the output of only one of the axis component that coincides with the power supply voltage component above or the axis component that is orthogonal to the axis A control apparatus for a grid-connected power conversion system, characterized by comprising means. In the voltage control, the control means outputs only one of the axis component that coincides with the power supply voltage component on the rotation coordinate that rotates synchronously with the power supply voltage of the power system or the axis component that is orthogonal to the axis. 2. The control apparatus for a grid-connected power conversion system according to claim 1, wherein when the magnitude of the rate of change of the output exceeds a set value, the magnitude of the rate of change of the output is limited.

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