JP7189653B2 - Power conversion system and controller - Google Patents

Description

TECHNICAL FIELD Embodiments of the present invention relate to power conversion systems and controllers.

A power conversion system is known that includes a main circuit section that performs at least one of conversion from AC power to DC power and conversion from DC power to AC power, and a control device that controls the operation of the main circuit section. . In such a power conversion system, two control devices are provided so that even if one control device fails, the other control device can continue operation.

A target value of the DC power is input to the control device. The control device calculates a DC power command value corresponding to the input target value and outputs the DC power command value, thereby controlling the operation of the main circuit unit so that the DC power approaches the target value.

In a power conversion system equipped with two control devices, when one control device is stopped and the other control device continues operation, the stopped control device is restored. It is necessary to match the DC power command values output from each. On the other hand, in order to suppress abrupt changes in the DC power command value, the control device performs rate processing for changing the DC power command value in a sloped manner with respect to the target value. Therefore, it takes time to match the DC power command values, and as a result, it may take time to complete the restoration of the control device. For example, when the rate speed of the rate processing is 1 MW/s and the target value is 300 MW, it takes about 5 minutes to complete the return to the control device at 300/60.

Therefore, in a power conversion system having two control devices, it is desirable to be able to restore the stopped control device more quickly.

JP 2018-129963 A

Embodiments provide a power conversion system and a control device that can be restored more quickly when one of the two control devices is restored from a stopped state.

A power conversion system according to an embodiment includes a main circuit unit that performs at least one of conversion from AC power to DC power and conversion from DC power to AC power, and controls the operation of the main circuit unit, one of which is stopped. and two control devices that enable the operation of the main circuit unit to continue even when the other side of the main circuit unit is operated, the two control devices, based on the target value of the DC power and a predetermined rate speed, A command value calculation unit that calculates a DC power command value for bringing the DC power closer to the target value, a communication unit that can acquire the DC power command value of the other control device by performing communication, When returning from the state in which the control related to the operation of the main circuit unit is stopped to the state in which the control is performed, the DC power command value of the other control device is acquired via the communication unit, and the command value is calculated. a control unit that matches the DC power command value calculated by the unit with the DC power command value of the other control device.

In this embodiment, a power conversion system and a control device are provided that can be restored more quickly when one of the two control devices is to be restored from a stopped state.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram which represents typically the power conversion system which concerns on embodiment. It is a block diagram which represents typically the control apparatus which concerns on embodiment. It is a block diagram which represents typically the command value calculating part which concerns on embodiment. FIGS. 4(a) and 4(b) are graph diagrams schematically showing an example of the time change of the DC power command value at the time of online restoration. It is a block diagram which represents typically the modification of the power conversion system which concerns on embodiment. It is a block diagram which represents typically the modification of the power conversion system which concerns on embodiment. It is a block diagram which represents typically the modification of the power conversion system which concerns on embodiment. It is a block diagram which represents typically the modification of the power conversion system which concerns on embodiment. It is a block diagram which represents typically the modification of the power conversion system which concerns on embodiment. It is a block diagram which represents typically the modification of the power conversion system which concerns on embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Note that the drawings are schematic or conceptual, and the relationship between the thickness and width of each portion, the size ratio between portions, and the like are not necessarily the same as the actual ones. Also, even when the same parts are shown, the dimensions and ratios may be different depending on the drawing.
In addition, in the present specification and each figure, the same reference numerals are given to the same elements as those described above with respect to the previous figures, and detailed description thereof will be omitted as appropriate.

FIG. 1 is a block diagram that schematically represents a power conversion system according to an embodiment.
As shown in FIG. 1 , the power conversion system 10 includes a main circuit section 12 and two controllers 14 and 16 .

The main circuit unit 12 performs at least one of conversion from AC power to DC power and conversion from DC power to AC power. The configuration of the main circuit section 12 may be any configuration capable of performing the above conversion.

The power conversion system 10 is used, for example, in a DC power transmission system that connects two AC power systems by transmitting DC power, or a frequency conversion system that connects two AC power systems with different frequencies. .

The two controllers 14 and 16 control the operation of the main circuit section 12 . The two controllers 14 , 16 control, for example, power conversion by the main circuit section 12 . The two controllers 14 and 16 allow the other to continue the operation of the main circuit section 12 even if one of them stops. As a result, for example, even when the control device 14 is stopped for repair or the like, the operation of the main circuit section 12 can be continued by the control device 16, and the operational stability of the power conversion system 10 can be enhanced.

The two controllers 14 and 16, for example, control part of the operation of the main circuit section 12. FIG. The control device 14 controls the operation of the first module of the main circuit section 12 . The control device 16 controls the operation of the second module of the main circuit section 12 . When the controllers 14, 16 are operating normally, they divide the outputs of the first and second modules equally. For example, when the target value of the DC power is 300 MW, control is performed by setting the DC power of each of the first module and the second module to 150 MW. When the control device 14 stops operating and the operation is continued only by the control device 16, the first module is stopped and the DC power of the second module is controlled to 300 MW. As a result, even if one stops, the other can continue to operate the main circuit section 12 . However, each of the controllers 14 and 16 may control the overall operation of the main circuit section 12 . When the controllers 14 and 16 are operating normally, the operation of the main circuit section 12 may be controlled by a control signal from either one of the controllers 14 and 16 .

FIG. 2 is a block diagram schematically showing the control device according to the embodiment.
As shown in FIG. 2 , the two control devices 14 and 16 have a command value calculation section 20, a communication section 22, and a control section 24. The construction of the two controllers 14, 16 is substantially the same.

A target value of DC power supplied from or to the main circuit unit 12 is input to the two controllers 14 and 16 . The target value is input to the control devices 14 and 16 from, for example, a host device (a host controller) or the like. For example, the target value may be manually input via an operation unit or the like.

The command value calculation unit 20 calculates a DC power command value for bringing the DC power closer to the target value based on the input target value of the DC power and the predetermined rate speed. The rate speed is, for example, 1 MW/s. The command value calculation unit 20 calculates the DC power command value, for example, so that the current DC power command value approaches the target value at a predetermined rate speed. For example, when the current DC power command value is 100 MW, the target value is 300 MW, and the rate speed is 1 MW/s, the command value calculation unit 20 calculates the DC power command value as 101 MW, and 102 MW one second later. and calculate. In this way, the command value calculator 20 sequentially updates the DC power command value based on the predetermined rate speed.

The control devices 14 and 16 control the operation of the main circuit section 12 based on the DC power command value calculated by the command value calculation section 20, for example. As a result, the DC power supplied from or to the main circuit section 12 can be brought closer to the target value.

The communication unit 22 enables acquisition of the DC power command value of the other control devices 14 and 16 by performing communication. In this example, the communication unit 22 directly acquires the DC power command value of the other control device 14 , 16 from the other control device 14 , 16 by communicating with the other control device 14 , 16 . That is, the communication unit 22 of the control device 14 directly acquires the DC power command value of the control device 16 from the control device 16 by communicating with the communication unit 22 of the control device 16 . Similarly, the communication unit 22 of the control device 16 directly acquires the DC power command value of the control device 14 from the control device 14 by communicating with the communication unit 22 of the control device 14 .

The control unit 24 acquires the DC power command value of the other control devices 14 and 16 via the communication unit 22 when returning from a state in which control related to the operation of the main circuit unit 12 is stopped to a state in which control is performed. In the power conversion system 10, as described above, even when the control device 14 is stopped for repair or the like, the operation of the main circuit section 12 can be continued by the control device 16. FIG. In this way, the recovery of the control device 14 or the control device 16 while the system continues to supply power (the main circuit unit 12 is performing conversion) is sometimes called online recovery. In other words, the control unit 24 acquires the DC power command value of the other control devices 14 and 16 via the communication unit 22 when the control devices 14 and 16 are restored online.

After acquiring the DC power command value of the other control device 14, 16 via the communication unit 22, the control unit 24 converts the DC power command value calculated by the command value calculation unit 20 into the DC power command value of the other control device 14, 16. Adjust to the DC power command value. That is, when the control device 14 is restored online, the control unit 24 of the control device 14 acquires the DC power command value of the control device 16 via the communication unit 22, and obtains the DC power command value calculated by the command value calculation unit 20. The value is adjusted to the DC power command value of the controller 16 . Similarly, the control unit 24 of the control device 16 acquires the DC power command value of the control device 14 via the communication unit 22 when the control device 16 is restored online, and the DC power calculated by the command value calculation unit 20 The command value is matched with the DC power command value of the controller 14 .

Further, after starting the online recovery process, the control unit 24 determines that the online recovery process has been completed when the DC current command value of the control device to be restored matches the DC current command value of the healthy control device. to decide. The controllers 14 and 16 start normal processing after completing the online recovery processing.

FIG. 3 is a block diagram schematically showing a command value calculator according to the embodiment.
As shown in FIG. 3 , the command value calculator 20 has a rate processing circuit 30 and a limiter 32 . As described above, the rate processing circuit 30 calculates a DC power command value for bringing the DC power closer to the target value based on the DC power target value and the predetermined rate speed.

The limiter 32 sets the upper limit and lower limit of the DC power command value calculated by the rate processing circuit 30 . Limiter 32 limits the DC power command value to the lower limit value when the DC power command value calculated by rate processing circuit 30 is smaller than the lower limit value. Limiter 32 limits the DC power command value to the upper limit value when the DC power command value calculated by rate processing circuit 30 is greater than the upper limit value. That is, the limiter 32 limits the DC power command value to a range equal to or greater than the lower limit value and equal to or less than the upper limit value. The command value calculator 20 outputs the DC power command value after passing through the limiter 32 as the final DC power command value.

In this example, the command value calculator 20 has a calculator 34 . Upper and lower limit values of the limiter 32 are input to the command value calculator 20 . The command value calculation unit 20 sets the input upper and lower limit values as the upper limit value of the limiter 32 and sets the upper and lower limit values multiplied by "-1" in the calculator 34 as the lower limit value of the limiter 32 . The upper limit value and the lower limit value of the limiter 32 are not limited to the above, and for example, the upper limit value and the lower limit value may be set individually. The upper limit value and lower limit value of the limiter 32 may be input to the command value calculation unit 20 via operation units provided in the control devices 14 and 16, or may be input to the command value calculation unit 20 from a host device or a lower device. can be entered in The upper limit value and lower limit value of the limiter 32 may be predetermined fixed values.

After obtaining the DC power command value of the other control device 14, 16 (the healthy system DC power command value), the control unit 24 sets the upper limit value and the lower limit value of the limiter 32 to the DC power of the other control device 14, 16. By setting the command value, the DC power command value calculated by the command value calculation unit 20 is matched with the DC power command value of the other control devices 14 and 16 .

The command value calculator 20 has switches 36 and 38, for example. The switch 36 switches between a state in which the predetermined upper limit value is set to the upper limit value of the limiter 32 and a state in which the DC power command value of the other control device 14 , 16 is set to the upper limit value of the limiter 32 . The switch 38 switches between a state in which the predetermined lower limit value is set to the lower limit value of the limiter 32 and a state in which the DC power command value of the other control devices 14 and 16 is set to the lower limit value of the limiter 32 .

The control unit 24 inputs a restoration command to the command value calculation unit 20 during online restoration. When the recovery command is input from the control unit 24 to the command value calculation unit 20, the control unit 24 determines whether or not the online recovery state is established. It may be automatically input to the calculation unit 20, or when the control unit 24 is instructed to execute the online restoration process from the operation unit provided in the control device 14, 16, the upper device, or the lower device. In response, it may be input from the control unit 24 to the command value calculation unit 20 .

The recovery command is, for example, a pulse signal that switches from Low to Hi during online recovery. The switches 36 and 38 switch to a state in which the DC power command value of the other control devices 14 and 16 is set to the lower limit value of the limiter 32 when the restoration command is input (when the restoration command becomes Hi). . As a result, the DC power command value calculated by the command value calculator 20 can be matched with the DC power command value of the other control devices 14 and 16 .

FIGS. 4(a) and 4(b) are graph diagrams schematically showing an example of the time change of the DC power command value at the time of online restoration.
FIG. 4(a) schematically represents an example of the operation of the control devices 14 and 16 according to the embodiment. FIG. 4(b) schematically represents an example of the operation of a reference control device that does not adjust the DC power command value. Here, the DC power command value of the control device that continues the operation of the main circuit unit 12 is the normal system DC power command value Pdp1, and the DC power command value of the control device that performs online restoration is the recovery system DC power command value. Description will be given as Pdp2.

In the control device that performs rate processing of the DC power command value, if the DC power command value is not adjusted, the difference between the command values Pdp1 and Pdp2, the rate speed, etc. Depending on the situation, it may take some time for the DC power command value Pdp2 for the recovery system to match the DC power command value Pdp1 for the normal system. As described above, the control devices 14 and 16 (control unit 24) determine that the online recovery is complete when the DC power command value Pdp2 for the recovery system matches the DC power command value Pdp1 for the healthy system. Therefore, in this case, it takes time to complete the online recovery.

On the other hand, in the control devices 14 and 16 according to the embodiment, the control unit 24 acquires the healthy system DC power command value Pdp1 via the communication unit 22, and the recovery system DC power command value Pdp1 calculated by the command value calculation unit 20 The power command value Pdp2 is adjusted to the healthy system DC power command value Pdp1. Therefore, as shown in FIG. 4A, immediately after the start of online recovery, the DC power command value Pdp2 for the recovery system can be matched with the DC power command value Pdp1 for the normal system. That is, online restoration can be completed immediately.

As described above, in the power conversion system 10 and the control devices 14 and 16 according to the present embodiment, when one of the two control devices 14 and 16 is restored from a stopped state, it can be restored more quickly.

FIG. 5 is a block diagram schematically showing a modification of the power conversion system according to the embodiment. It should be noted that the same reference numerals are given to the parts that are substantially the same as those of the above-described embodiment in terms of function and configuration, and detailed description thereof will be omitted.
As shown in FIG. 5, the power conversion system 10a further includes a host device 50. FIG. The host device 50 inputs target values to the two control devices 14 and 16 .

The communication unit 22 acquires the DC power command values of the other control devices 14 and 16 via the host device 50 by communicating with the host device 50 . In this manner, the healthy system DC power command value may be acquired via the host device 50 . In this case, the communication section 22 does not necessarily have the function of communicating with the communication section 22 of the other control device 14 , 16 .

FIG. 6 is a block diagram schematically showing a modification of the power conversion system according to the embodiment. As shown in FIG. 6, the power conversion system 10b further includes two host devices 51 and 52 . The two host devices 51 and 52 input target values to the two control devices 14 and 16, respectively.

In this case, the communication unit 22 communicates with one of the two host devices 51 and 52 to transmit the DC power command value of the other control devices 14 and 16 via the one of the host devices 51 and 52. to get. In this way, when a plurality of host devices are connected to the control devices 14 and 16, the normal DC power command value may be acquired via any one of the plurality of host devices.

FIG. 7 is a block diagram schematically showing a modification of the power conversion system according to the embodiment. As shown in FIG. 7, in the power conversion system 10c, the two host devices 51 and 52 individually input target values to the two control devices 14 and 16, respectively. Also, the two host devices 51 and 52 communicate with each other.

In this case, the communication unit 22 acquires the DC power command value of the other control devices 14 and 16 via the two host devices 51 and 52 . In this way, when the host devices 51 and 52 are connected to the control devices 14 and 16, respectively, the normal DC power command value may be acquired via the host devices 51 and 52, respectively.

Drawing 8 is a block diagram showing typically the modification of the power conversion system concerning an embodiment. As shown in FIG. 8, the power conversion system 10d further includes a lower device 60. As shown in FIG. The subordinate device 60 controls the operation of the main circuit section 12 based on the DC power command values input from the two control devices 14 and 16 . The lower device 60 controls the operation of the main circuit section 12, for example, based on the DC power command value. However, the control performed by the lower device 60 may be any control related to the operation of the main circuit section 12 .

The communication unit 22 acquires the DC power command value of the other control devices 14 and 16 via the lower device 60 by communicating with the lower device 60 . In this way, the healthy system DC power command value may be acquired via the lower device 60 . Also in this case, the communication unit 22 does not necessarily have to have the function of communicating with the communication unit 22 of the other control device 14 , 16 .

FIG. 9 is a block diagram schematically showing a modification of the power conversion system according to the embodiment. As shown in FIG. 9, the power conversion system 10e further includes two sub-devices 61 and 62. The two subordinate devices 61 and 62 control the operation of the main circuit section 12 based on the DC power command values input from the two control devices 14 and 16, respectively.

In this case, the communication unit 22 communicates with one of the two lower devices 61 and 62 to transmit the DC power command value of the other control device 14 and 16 via either one of the lower devices 61 and 62. to get. In this way, when a plurality of subordinate devices are connected to the control devices 14 and 16, the normal DC power command value may be obtained via any one of the plurality of subordinate devices.

FIG. 10 is a block diagram schematically showing a modification of the power conversion system according to the embodiment.
As shown in FIG. 10, in the power conversion system 10f, two subordinate devices 61 and 62 are provided corresponding to the two control devices 14 and 16, respectively. The operation of the main circuit unit 12 is controlled based on the DC power command value. Also, the two subordinate devices 61 and 62 communicate with each other.

In this case, the communication unit 22 acquires the DC power command value of the other control devices 14 and 16 via the two lower devices 61 and 62 . In this way, when the subordinate devices 61 and 62 are connected to the control devices 14 and 16, respectively, the normal DC power command value may be obtained via the subordinate devices 61 and 62, respectively.

In each of the above embodiments, the power conversion system provided with two control devices 14 and 16 is shown, but the number of control devices provided in the power conversion system is not limited to two, and may be three or more. . Even when three or more control devices are provided, during online recovery, the DC power command value of the healthy system is acquired, and the DC power command value of the restored system is adjusted to the DC power command value of the healthy system. Similar to the above, it is possible to quickly restore the control device of the restoration system and quickly complete the online restoration. The two controllers 14, 16 may be two controllers of three or more controllers.

Although several embodiments of the invention have been described above, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included within the scope and spirit of the invention, and are included within the scope of the invention described in the claims and equivalents thereof. Moreover, each of the above-described embodiments can be implemented in combination with each other.

10, 10a to 10f power conversion system 12 main circuit section 14 control device 16 control device 20 command value calculation section 22 communication section 24 control section 30 rate processing circuit 32 limiter 34 calculator 36 switch device, 38 switch, 50, 51, 52 upper device, 60, 61, 62 lower device

Claims (10)

a main circuit unit that performs at least one of conversion from AC power to DC power and conversion from DC power to AC power;
two controllers for controlling the operation of the main circuit unit and for allowing the other to continue the operation of the main circuit unit even if one of them stops;
with
The two controllers are
a command value calculation unit that calculates a DC power command value for bringing the DC power closer to the target value based on the target value of the DC power and a predetermined rate speed;
a communication unit capable of acquiring the DC power command value of the other control device by performing communication;
When returning from the state in which the control related to the operation of the main circuit unit is stopped to the state in which the control is performed, the DC power command value of the other control device is acquired via the communication unit, and the command value is calculated. a control unit that matches the DC power command value calculated by the unit with the DC power command value of the other control device;
A power conversion system having The command value calculation unit has a limiter that sets an upper limit value and a lower limit value of the DC power command value,
After obtaining the DC power command value of the other control device, the control unit sets the upper limit value and the lower limit value of the limiter to the DC power command value of the other control device, thereby 2. The power conversion system according to claim 1, wherein the DC power command value calculated by the command value calculation unit is matched with the DC power command value of the other control device. The power conversion according to claim 1 or 2, wherein the communication unit directly acquires the DC power command value of the other control device from the other control device by communicating with the other control device. system. Further comprising a host device that inputs the target value to the two control devices,
The power conversion system according to claim 1 or 2, wherein the communication unit acquires the DC power command value of the other control device via the host device by communicating with the host device. Further comprising two host devices for inputting the target value to each of the two control devices,
3. The communication unit acquires the DC power command value of the other control device via one of the two host devices by communicating with one of the two host devices. The power conversion system according to . further comprising two host devices that individually input the target values to the two control devices;
the two host devices communicate with each other;
The power conversion system according to claim 1 or 2, wherein the communication unit acquires the DC power command value of the other control device via the two host devices. Further comprising a lower device for controlling the operation of the main circuit unit based on the DC power command value input from the two control devices,
The power conversion system according to claim 1 or 2, wherein the communication unit acquires the DC power command value of the other control device via the lower device by communicating with the lower device. Further comprising two sub-devices for controlling the operation of the main circuit unit based on the DC power command value input from each of the two control devices,
3. The communication unit acquires the DC power command value of the other control device via one of the two subordinate devices by communicating with one of the two subordinate devices. The power conversion system according to . Further two subordinate devices are provided corresponding to each of the two control devices and perform control related to the operation of the main circuit unit based on the DC power command value input from one of the two control devices. prepared,
the two subordinate devices communicate with each other;
The power conversion system according to claim 1 or 2, wherein the communication unit acquires the DC power command value of the other control device via the two lower devices. a main circuit unit that performs at least one of conversion from AC power to DC power and conversion from DC power to AC power;
two controllers for controlling the operation of the main circuit unit and for allowing the other to continue the operation of the main circuit unit even if one of them stops;
A control device used in a power conversion system comprising
a command value calculation unit that calculates a DC power command value for bringing the DC power closer to the target value based on the target value of the DC power and a predetermined rate speed;
a communication unit capable of acquiring the DC power command value of the other control device by performing communication;
When returning from the state in which the control related to the operation of the main circuit unit is stopped to the state in which the control is performed, the DC power command value of the other control device is acquired via the communication unit, and the command value is calculated. a control unit that matches the DC power command value calculated by the unit with the DC power command value of the other control device;
control device with

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