JP2019140738A - Power conversion apparatus - Google Patents

Abstract

To provide a power conversion apparatus in which the total extension of an optical fiber cable is not increased and operation of a power converter can be continued even when any one of unit converters has a failure.SOLUTION: A power conversion apparatus according to an embodiment includes: a power converter including a plurality of unit converters cascade-connected to each other; a control device that transmits, as a first optical signal, serial data including first data for controlling the plurality of unit converters and receives, as a second optical signal, second data indicating the respective states of the plurality of unit converters; and optical distribution means for distributing the first optical signal to each of the plurality of unit converters, joining the second data collected from the plurality of unit converters and converted to optical signals so as not to overlap with each other, and transmitting the joined data as the second optical signal.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a power conversion apparatus.

  A modular multilevel converter (hereinafter referred to as MMC) is put to practical use as a power conversion system that can realize a large capacity while achieving a reduction in size by using a self-extinguishing semiconductor switching element. Is underway.

  In the MMC, the control device receives data such as capacitor voltage from a large number of unit converters, generates a gate signal for operating the unit converter, and transmits it to each unit converter.

  In order to increase the output capacity by increasing the number of unit converters connected in cascade, it is necessary to use many long optical fiber cables for data transmission between the control device and the unit converter.

  A technique for shortening the total length of an optical fiber cable by connecting transmission paths for data transmission in a loop with a daisy chain is known (Patent Document 1, etc.). However, when a failure occurs in the unit converter in the middle of the daisy chain, data cannot be transmitted / received, and the operation of the power converter cannot be continued. When the operation is continued by making the data transmission path redundant as in Patent Document 1, the total length of the optical fiber cable increases depending on the degree of redundancy.

JP 2014-42390 A

  The embodiment provides a power conversion device capable of continuing the operation of the power converter without increasing the total extension of the optical fiber cable and even if any unit converter fails.

  A power conversion device according to an embodiment includes a power converter including a plurality of unit converters connected in cascade and serial data including first data for controlling each of the plurality of unit converters as a first light. A control device that transmits as a signal and receives second data representing a state of each of the plurality of unit converters as a second optical signal; and distributes the first optical signal to each of the plurality of unit converters. And optical distribution means for combining the second data collected from each of the plurality of unit converters and converted into an optical signal so as not to overlap and transmitting the second data as the second optical signal.

  In the present embodiment, the optical distribution unit distributes the first optical signal to each of the plurality of unit converters, collects the second data collected from the plurality of unit converters and converted into optical signals. The signals are combined so as not to overlap and transmitted as a second optical signal. Therefore, data transmission between the control device and the unit converter does not need to be a loop-shaped daisy chain connection. Therefore, the power conversion device can continue to operate without increasing the total length of the optical fiber cable due to redundancy of the daisy chain and even if any unit converter fails.

It is a block diagram which illustrates the power converter concerning a 1st embodiment. It is a block diagram which illustrates a part of power converter of a 1st embodiment. It is a notional schematic diagram for demonstrating operation | movement of the power converter device of 1st Embodiment. It is an example of a typical timing chart for explaining operation of the power converter of a 1st embodiment. FIG. 5A and FIG. 5B are conceptual schematic diagrams for explaining the operation of the power conversion device of the comparative example. It is the simplified block diagram which illustrates a part of power converter device concerning a 2nd embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between the parts, and the like are not necessarily the same as actual ones. Further, even when the same part is represented, the dimensions and ratios may be represented differently depending on the drawings.
In the present specification and drawings, the same elements as those described above with reference to the previous drawings are denoted by the same reference numerals, and detailed description thereof is omitted as appropriate.

(First embodiment)
FIG. 1 is a block diagram illustrating a power conversion apparatus according to this embodiment.
As shown in FIG. 1, the power conversion device 10 of this embodiment includes a power converter 20, an optical distributor 40, and a control device 50. The power conversion device 10 is connected to the AC power system 1 through AC terminals 21a to 21c. As in this example, the power conversion device 10 may be connected to the power system 1 via the transformer 2. For example, the electric power system 1 can be configured to include a three-phase or single-phase 50 Hz or 60 Hz power source, a load, and an AC power transmission line. For example, the power conversion device 10 is connected to the DC circuit 3 through the DC terminals 21d and 21e. DC circuit 3 includes, for example, a DC transmission line. In the following, it is assumed that the power conversion device 10 is linked to the three-phase power system 1.

  The power conversion device 10 is connected between the power system 1 and the DC circuit 3 and can perform bidirectional power conversion between AC and DC.

  In the power conversion device 10, the control device 50 and the optical distributor 40 are connected via an optical fiber cable 60 and transmit data to each other. The optical distributor 40 and the power converter 20 are connected via an optical fiber cable 42 and transmit data to each other. That is, the control device 50 can transmit data to and from the power converter 20 via the optical fiber cable 60, the optical distributor 40, and the optical fiber cable 42.

  The power converter 20 is installed on the insulating mount 26. The insulating mount 26, the light distributor 40, and the control device 50 can be mounted on the same installation surface 4. The insulating mount 26 is made of an insulating material, and the power converter 20 is electrically insulated from the optical distributor 40 and the control device 50. The installation surface 4 on which the insulating gantry 26, the light distributor 40, and the control device 50 are placed has substantially the same potential, and may be physically different surfaces. For example, the insulating mount 26 and the light distributor 40 are placed on the floor surface of the control room on the second floor of the building, the control device 50 is placed on the floor surface of the first floor of the same building, etc. Also good.

  The power converter 20 includes an arm 22 corresponding to each phase of the three-phase alternating current. The arm 22 is connected in series between the DC terminals 21d and 21e.

  A buffer reactor 24 is connected in series to each of the arms 22 connected in series between the DC terminals 21d and 21e. The buffer reactor 24 prevents an instantaneous short-circuit current from flowing between the upper and lower arms 22.

  The taps of the buffer reactor 24 are connected to the AC terminals 21a to 21c, respectively.

  The arm 22 includes unit converters 30 connected in cascade. In the following description, it is assumed that M unit converters 30 are connected in series to one arm 22 (M is an integer of 2 or more).

FIG. 2 is a block diagram illustrating a part of the power conversion apparatus of this embodiment.
As shown in FIG. 2, the unit converter 30 includes terminals 31a and 31b. The unit converter 30 is cascade-connected to other unit converters 30 and the like by terminals 31a and 31b. The unit converter 30 includes a photoelectric conversion unit 32, a control circuit 33, a gate driver 34, a main circuit 35, a main circuit power supply unit 36, and a voltage detector 37.

  The photoelectric conversion unit 32 is connected to a pair of inputs and outputs of the optical distributor 40 via an optical fiber cable 42. The photoelectric conversion unit 32 receives the optical signal including the station number of the unit converter 30 output from the optical distributor 40 and the control data corresponding to the station number, and converts it into an electrical signal. The converted electrical signal is supplied to the control circuit 33. The station number is a number for specifying the unit converter 30 and, for example, a serial number is given in advance for each unit converter 30.

  In the control circuit 33, the station number of the unit converter 30 is registered in advance. The control circuit 33 interprets data included in the electrical signal supplied from the photoelectric conversion unit 32 and acquires control data (first data) that matches the station number of itself. The control data includes, for example, phase data of gate signals for driving the switching elements 35S1 and 35S2. The control circuit 33 generates a gate signal based on the control data. The generated gate signal is supplied to the gate driver 34.

  The control circuit 33 supplies data representing the state of the unit converter 30 in association with the unit converter 30 to the photoelectric conversion unit 32 in association with its own station number. This data is, for example, measurement data of the voltage value across the capacitor 35C. The voltage value Vc of the capacitor 35C is measured by the voltage detector 37. Hereinafter, data representing the state of the unit converter 30 and the like will be referred to as converter data (second data).

  When supplying data to the photoelectric conversion unit 32, the control circuit 33 adds the transmission delay time Tx corresponding to its own station number x and supplies it. The transmission delay time Tx is a unit of another station number in order to combine the data transmitted to the control device 50 with the data of the other unit converter 30 into the substantial serial data in the optical distributor 40. It is set not to overlap with the data of the converter 30. The transmission delay time Tx is set to be equal to or longer than the length of data output from the unit converter 30, for example.

  For example, the station number of the unit converter 30 is set in ascending order from “1”, and the data order in the serial data transmitted from the power converter 20 to the control device 50 is set in ascending order of the station number. The explanation is as follows.

  When the station number is “1”, the transmission delay time T1 = 0 is set. If the station number is “2”, the transmission delay time T2 = Tw is set. Tw is set based on the length of data supplied by the control circuit 33. Tw is set to be longer than the length of data supplied by the control circuit 33, for example. When the station number is “3”, the delay time T3 = 2 × Tw is set.

  The gate driver 34 converts the level of the gate signal supplied from the control circuit 33 and outputs it. The level-converted gate signal is supplied to the main circuit 35 as a gate drive signal.

  Main circuit 35 includes switching elements 35S1 and 35S2, diodes 35D1 and 35D2, and a capacitor 35C. The switching elements 35S1 and 35S2 are connected in series. The diodes 35D1 and 35D2 are connected in antiparallel to the switching elements 35S1 and 35S2, respectively. The capacitor 35C is connected in parallel to the series circuit of the switching elements 35S1 and 35S2.

  The switching elements 35S1 and 35S2 are self-extinguishing semiconductor switches such as IGBTs (Insulated Gate Bipolar Transistors). Switching elements 35S1 and 35S2 are driven by a gate drive signal supplied from gate driver 34, and charge / discharge capacitor 35C.

  The main circuit is not limited to the half-bridge circuit as described above, and may be a full-bridge circuit using four switching elements.

  The main circuit power supply unit 36 receives power supply from the capacitor 35C, converts it to an appropriate voltage, and supplies it to the photoelectric conversion unit 32, the control circuit 33, and the gate driver 34, respectively.

  Returning to FIG. 1, the description will be continued. The optical distributor 40 is connected to the photoelectric conversion unit 52 of the control device 50 via the optical fiber cable 60. The optical distributor 40 is connected to the photoelectric conversion unit 32 of the unit converter 30 via an optical fiber cable 42. The optical distributor 40 distributes the optical signal transmitted from the control device 50 to each of the plurality of unit converters 30 by an optical fiber cable 42 corresponding to the unit converter 30 (not shown in the figure). The optical distributor 40 merges each optical signal data transmitted from the plurality of unit converters 30 into one optical signal data, thereby substantially converting it into serial data and transmitting it to the control device 50.

  The optical distributor 40 can be installed in the vicinity of the power converter 20. Therefore, the optical fiber cable 42 can be made long enough to be installed in the power converter 20. The control device 50 can be installed at a location sufficiently away from the power converter 20 and the optical distributor 40. For example, the control device 50 may be installed in a building or a floor different from the installation location of the light distributor 40 and the power converter 20. The length of the optical fiber cable 42 can be made sufficiently shorter than the length of the optical fiber cable 60.

  The control device 50 includes a photoelectric conversion unit 52. The photoelectric conversion unit 52 is connected to the optical fiber cable 60. The photoelectric conversion unit 52 converts serial data generated in other parts of the control device 50 into an optical signal and transmits the optical signal to the power converter 20 via the optical fiber cable 60. The serial data includes control data corresponding to the unit converter 30. The photoelectric conversion unit 52 converts the data received from the power converter 20 into an electric signal and supplies it to the other part of the control device 50. In other parts of the control device 50, processing for generating the next control data is executed.

Operation | movement of the power converter device of this embodiment is demonstrated.
FIG. 3 is a conceptual schematic diagram for explaining the operation of the power conversion device of the present embodiment.
As shown in FIG. 3, data is transmitted between the control device 50 and the optical distributor 40 via the optical fiber cable 60. In the figure, the optical fiber cables 60 and 42 are indicated by arrows so as to indicate the direction of data flow.

  Data is transmitted between the optical distributor 40 and the unit converter (cell) 30 via an optical fiber cable 42. In the power conversion device 10 of the present embodiment, the data format between the optical distributor 40 and the unit converter 30 differs depending on the data transmission direction. Hereinafter, the unit converter 30 of the station number x is referred to as “cell x”. Also, x is an integer from 1 to N, and N represents the total number of unit converters 30 (N = 6 × M in this example).

First, a case where data is transmitted from the control device 50 to the power converter 20 will be described.
Each of the cells 1 to N of the power converter 20 is set with a station number x for identifying itself. The station number x is arbitrarily set. For example, the station number x is set by assigning a serial number to all cells included in the power converter 20. Station number 1 is set in cell 1, station number 2 is set in cell 2, and similarly, station number N is set in cell N.

  The data transmitted to the power converter 20 by the control device 50 includes a station number x that identifies a cell and control data Ax that corresponds to the station number.

  The control device 50 generates these control data Ax. The photoelectric conversion unit 52 converts the set of the generated station number x and control data Ax into serial data AS and converts it into an optical signal. The serial data AS * converted into the optical signal is transmitted to the optical distributor 40 via the optical fiber cable 60.

  The optical distributor 40 distributes the received serial data AS * to the cells 1 to N, respectively. That is, for example, serial data AS * is transmitted to cell 1, and serial data AS * is also transmitted to cell 2. Similarly, the same serial data AS * is transmitted to all cells.

  As already described in FIG. 2, the serial data AS * is input to the photoelectric conversion unit 32 in the cell. The photoelectric conversion unit 32 converts the optical signal serial data AS * into electrical signal serial data AS. The photoelectric conversion unit 32 supplies the serial data AS to the control circuit 33. The control circuit 33 searches for the own station number x from the received serial data AS, and obtains the control data Ax associated with the station number x. Each cell operates based on the acquired control data Ax.

Next, a case where data is transmitted from the power converter 20 to the control device 50 will be described with reference to FIGS. 3 and 4.
FIG. 4 is an example of a schematic timing chart for explaining the operation of the power conversion device of the present embodiment.
As illustrated in FIG. 4, the control device 50 generates a request signal RQ that requests the power converter 20 to transmit data. The control device 50 converts the request signal RQ into an optical request signal RQ * by the photoelectric conversion unit 52 and transmits the request signal RQ *.

  The request signal RQ * is transmitted to the optical distributor 40. The optical distributor 40 distributes the request signal RQ * to the cells 1 to N, respectively.

  Each of the cells 1 to N is converted into an electrical request signal RQ by the photoelectric conversion unit 32, and the data transmission request is interpreted by the control circuit 33.

  In the cells 1 to N, the control circuit 33 acquires data related to the main circuit 35, for example, and generates converter data Bx associated with its own station number x. When transmitting the combination of the station number x and the converter data Bx, the control circuit 33 adds the transmission delay time Tx and transmits it. The transmission delay time Tx is set according to the length of data to be transmitted and the position in the case of serial data.

  The control circuit 33 supplies the set of the station number x and the converter data Bx associated with the station number x to the photoelectric conversion unit 32 after the set transmission delay time Tx has elapsed.

  In this example, the data set of cell 1 is set without transmission delay time. The data set of the cell 2 is transmitted after the transmission delay time Tw so as to be transmitted following the data set of the cell 1. The data set of the last cell N is transmitted after transmission delay time (N−1) × Tw.

  The photoelectric conversion unit 32 converts each data set to which the transmission delay time is added into an optical signal and supplies the optical signal to the optical distributor 40.

  The optical distributor 40 sequentially sends a set of data sequentially transmitted from each unit converter 30 to the optical fiber cable 60. Since the set of data sent sequentially does not overlap, it is transmitted to the control device 50 as substantially one serial data BS * (FIG. 3).

  The photoelectric conversion unit 52 of the control device 50 converts the serial data BS * of the optical signal into serial data BS of the electrical signal. The control device 50 acquires the converter data Bx of the serial data BS in association with the station number x and executes a predetermined process.

  The transmission delay time Tx is set to (x−1) × Tw according to the station number x. However, this relationship is not necessarily required if adjacent data do not overlap when the data is merged. It is not limited to. For example, Tw ′> Tw may be set so as to satisfy Tx = (x−1) × Tw ′, or may be set individually for each unit converter.

  In the above description, the serial data AS, AS * are arranged in the ascending order of the station number x, and a set of data including the control data Ax is arranged. The data set was arranged. However, the arrangement order and transmission order of these data are not limited to this. When transmitting from the power converter 20 to the control device 50, the data sets of the converter data Bx may be substantially serial data without overlapping each other. That is, the transmission order of the converter data Bx may be set in advance, and the transmission delay time Tx corresponding to the order may be set for the set of converter data Bx. For example, the order of the set of control data in the serial data AS may be different from the order of the set of converter data Bx in the substantial serial data Bx. In addition, any data may be in the descending order or random as well as the ascending order of the station numbers.

The effect of the power converter of this embodiment is demonstrated, comparing with the case of the power converter of a comparative example.
FIG. 5A and FIG. 5B are conceptual schematic diagrams for explaining the operation of the power conversion device of the comparative example.
FIG. 5 (a) shows an example in which an optical fiber cable 160a, which is a transmission path in which each unit converter 130a is daisy chain connected, is used for data transmission between the control device 150a and the power converter 120a. ing.

  The unit converter (cell 1) 130a receives the serial data CS * transmitted from the control device 50 by the photoelectric conversion unit. The serial data CS, CS * includes a station number x, control data Ax and converter data Bx associated with the station number x.

  The photoelectric conversion unit converts the serial data CS * into serial data CS of an electrical signal, and supplies the converted serial data CS to the control circuit. The control circuit acquires the control data A1 of its own station number 1, and updates the serial data CS with the converter data B1.

  The updated serial data CS is transferred to the unit converter (cell 2) 130a daisy chained by the optical fiber cable 160a. Similar to the cell 1, the unit converter 130a acquires the control data A2 corresponding to its own station number from the serial data, and updates the serial data CS with the converter data B2.

  The above operation is performed in all the unit converters 130a, and the last unit converter (cell N) 130a transmits the serial data CS and CS * to the control device 50 through the optical fiber cable 160a.

  As described above, in the power conversion device of the comparative example, in the data transmission between the control device 150a and the unit converter 130a, a loop-shaped transmission path using a daisy chain that interconnects the unit converters 130a is used. Yes. For this reason, when a failure occurs in the unit converter 130a in the middle of the daisy chain, control data cannot be transferred from the control device 150a, and the converter data acquired by the unit converter up to that time is updated. You can not do. Therefore, it becomes difficult to continue operation as a power converter.

  FIG. 5B shows an example in which an optical fiber cable 160b corresponding to each unit converter 130b of the power converter 120b is provided for data transmission between the control device 150b and the power converter 120b. Has been.

  As shown in FIG. 5B, the control device 150b does not convert the data to be transmitted to all the unit converters 130b into serial data, but as control data Ax corresponding to the unit converter 130b of the station number x. The converter Bx data transmitted from each unit converter 130b is acquired.

  According to such a configuration, even if a failure occurs in any of the unit converters, the transmission of the control data Ax and the converter data Bx is not interrupted, so that the power converter can continue operation. it can.

  However, it is necessary to provide the optical fiber cable 160b between the control device 150b and the power converter 120b according to the number of unit converters 130b. In the MMC, the number of unit converters per arm may reach several tens to 100 or more, and when a large number of long-distance optical fiber cables are used, the cost may increase.

  In contrast to the above-described comparative example, in the case of the present embodiment, since the optical distributor 40 is provided, the number of the optical fiber cables 60 that lay a long distance between the control device 50 and the power converter 20 is reduced. Can be reduced. In the power converter 20, since data is transmitted between the optical distributor 40 and each unit converter 30, even if any unit converter 30 fails, other unit converters There will be no deficiencies in control data and converter data. Therefore, the power conversion device 10 can continue the operation.

  The optical distributor 40 is electrically insulated from the power converter 20 by the insulating mount 26. Therefore, the optical distributor 40 can be installed in the vicinity of the power converter 20 without special consideration for installation.

  Further, in the power conversion device 10 of the present embodiment, data is not sequentially transferred through the transmission paths connected in a daisy chain, so that the time required for data setting and acquisition can be shortened. Therefore, it becomes possible to improve the response characteristics of the control.

(Second Embodiment)
In the above-described embodiment, when data is transmitted from the power converter to the control device, a transmission delay time is set for each unit converter, and the optical signal data is merged and transmitted as substantially serial data. . In the embodiment described below, a transmission delay time setting mechanism is provided in the optical distributor to generate substantial serial data.

FIG. 6 is a simplified block diagram illustrating the power conversion apparatus according to this embodiment.
As illustrated in FIG. 6, the power conversion device 210 includes a power converter 220, an optical distributor 240, and a control device 50. The power converter 220 is an MMC converter including unit converters 230 connected in cascade. In FIG. 6, the configuration of the power converter 220 is shown in a simplified manner, and the detailed configuration of the power converter 220 is the same as that in FIG. 1.

  Unit converter 230 includes a control circuit 233. Other components are the same as those of the unit converter 30 in the embodiment described above.

  The optical distributor 240 includes photoelectric conversion units 241 and 242 and a signal processing circuit 243. The other end of the optical fiber cable 60 whose one end is connected to the control device 50 is connected to the photoelectric conversion unit 241. As many photoelectric conversion units 242 as the number of unit converters 230 are provided. When the unit converter (cell) 230 is N power converters 220, N photoelectric conversion units 242 are provided. The signal processing circuit 243 is connected between the photoelectric conversion unit 241 on the control device side and the photoelectric conversion unit 242 on the unit converter 230 side.

  The signal processing circuit 243 converts serial data transmitted from the control device 50 and converted into an electric signal by the photoelectric conversion unit 241 into data for each unit converter. The signal processing circuit 243 supplies the data for each unit converter to the photoelectric conversion unit 242 corresponding to the unit converter.

  The signal processing circuit 243 converts the converter data transmitted from each unit converter 230 and converted into an electric signal by the photoelectric conversion unit 242 sequentially, for each converter data, a transmission delay time Tx corresponding to the unit converter. It is added and supplied to the photoelectric conversion unit.

  In this embodiment, when transmitting data from the power converter to the control device, the optical distributor may have another configuration as long as transmission delay time can be added to the data output from the unit converter. Absent. For example, the signal processing circuit may transmit the serial data as it is without being decomposed into the data for each unit converter 230 from the serial data transmitted from the control device 50. The signal processing circuit 243 adds the transmission delay time to the data transmitted from the unit converter 230 as described above. Alternatively, the serial data transmitted from the control device 50 may be transmitted to each unit converter 230 without going through the signal processing circuit.

Operation | movement of the power converter device 210 of this embodiment is demonstrated.
First, a case where data is transmitted from the control device 50 to the power converter 220 will be described.
Data transmitted from the control device 50 is the same as in the other embodiments described above. That is, the combination data of the station number x set for each unit converter 230 and the setting data Dx corresponding to the station number x is converted into serial data AS, and further the serial data of the optical signal by the photoelectric conversion unit 52 of the control device 50. It is converted to AS * and transmitted.

  The serial data AS * is transmitted to the optical distributor 240 of the power converter 220. The photoelectric conversion unit 241 of the optical distributor 240 converts the serial data AS * into serial data AS of an electrical signal. The converted serial data AS is supplied to the signal processing circuit 243.

  The signal processing circuit 243 converts the serial data AS into data for each station number and supplies the data to each photoelectric conversion unit 242. Each photoelectric conversion unit 242 is connected to the photoelectric conversion unit of the unit converter 230 having a corresponding station number by an optical fiber cable 42.

  The photoelectric conversion unit 242 transmits the converter data Bx * to the unit converter 230 having the corresponding station number x via the optical fiber cable 42. The unit converter 230 that has received the converter data Bx * converts the converter data Bx * into the converter data Bx of an electric signal, and drives a switching element, for example, according to the converted converter data Bx.

Next, a case where data is transmitted from the power converter 220 to the control device 50 will be described.
In each unit converter 230 of the power converter 220, the control circuit 33 acquires, for example, converter data Bx related to the main circuit 35, and supplies it to the photoelectric conversion unit in association with its own station number x.

  The photoelectric conversion unit converts the converter data Bx into an optical signal Bx * and supplies the optical signal Bx * to the photoelectric conversion unit 242 of the optical distributor 240.

  The signal processing circuit 243 acquires the converter data Bx corresponding to each station number via the photoelectric conversion unit 242 corresponding to each unit converter 230.

  The signal processing circuit 243 adds the transmission delay time Tx to the converter data Bx and combines it with other converter data to generate serial data.

  The signal processing circuit 243 supplies the generated serial data to the photoelectric conversion unit 241, and the photoelectric conversion unit 241 converts the serial data into an optical signal and transmits it to the control device 50.

  The control device 50 converts the serial data of the optical signal into an electrical signal, and acquires converter data corresponding to the station number.

  In this way, in the power conversion device of this embodiment, even if any unit converter fails, it is possible to transmit data to and from the control device without increasing the number of optical fiber cables. Can do.

  Moreover, in this embodiment, since it can implement | achieve easily by additionally mounting the signal processing circuit 243 with respect to one optical divider | distributor 240, it implement | achieves also by the modification of the existing power converter. Can do.

  According to the embodiment described above, even if any unit converter breaks down, it is possible to transmit the data between the control device and the power converter and to realize the power converter that can continue the operation. Can do.

  As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and the equivalents thereof. Further, the above-described embodiments can be implemented in combination with each other.

  DESCRIPTION OF SYMBOLS 1 Power system, 2 Transformer, 3 DC circuit, 10 Power converter, 20, 220 Power converter, 22 Arm, 24 Buffer reactor, 30, 230 Unit converter, 32,232 Photoelectric conversion part, 33,233 Control circuit , 34 Gate driver, 35 Main circuit, 36 Main circuit power supply unit, 40, 240 Optical distributor, 42 Optical fiber cable, 50 Control device, 52 Photoelectric conversion unit, 60 Optical fiber cable, 241, 242 Photoelectric conversion unit, 243 signal Processing circuit

Claims (6)

A power converter including a plurality of unit converters connected in cascade;
Serial data including first data for controlling each of the plurality of unit converters is transmitted as a first optical signal, and second data representing each state of the plurality of unit converters is used as a second optical signal. A control device for receiving;
The first optical signal is distributed to each of the plurality of unit converters, collected from each of the plurality of unit converters, and the second data converted into the optical signal is joined so as not to overlap. Optical distribution means for transmitting as the second optical signal;
The power converter provided with.   2. The power conversion device according to claim 1, wherein each of the plurality of unit converters sets a transmission delay time according to the second data of the unit converter and transmits the second data to the optical distribution unit.   2. The power converter according to claim 1, wherein the optical distribution unit sets a transmission delay time corresponding to each of the plurality of unit converters and merges the second data transmitted from the plurality of unit converters. .   The power conversion device according to claim 3, wherein the light distribution unit includes a signal processing circuit that generates the delay time for each of the plurality of unit converters.   5. The power conversion device according to claim 2, wherein the transmission delay time is set according to a length of the second data for each of the plurality of unit converters. The power converter is installed on an insulating mount formed of an insulating material,
The power converter according to any one of claims 1 to 5, wherein the insulating mount can be installed at the same potential as the light distribution means.

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