JP6214092B2 - Power converter - Google Patents

Description

  The present invention relates to a power conversion device.

  In general, an MMC (modular multilevel converter) is known as a self-excited power converter. The MMC is a power conversion device configured with a plurality of cells (unit converters). The MMC is controlled by a gate pulse (gate signal) input to each cell. An optical fiber cable is used for transmission of the gate pulse. In order to shorten the optical fiber cable, it is disclosed that each cell is daisy chain connected with an optical fiber cable and an optical serial signal is transmitted to each cell (for example, see Patent Document 1).

JP 2011-24393 A

  However, when a gate signal is transmitted to cells connected in a daisy chain by serial communication, if an abnormality occurs in the transmission line, a problem for continued operation of the power conversion device becomes large. For example, when a gate signal is transmitted to all cells by one line, if any part of the one line (for example, a cell) becomes abnormal, it cannot be transmitted to all cells. Therefore, in such a configuration, the operation of the power conversion device cannot be continued due to an abnormality in one line.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a power conversion device having a high continuity of operation for an abnormality in a line through which a plurality of unit converters perform serial communication and perform serial communication.

A power conversion device according to an aspect of the present invention includes a plurality of unit converters constituting a power conversion circuit, and a control for transmitting a transmission signal of an optical signal including information for controlling the plurality of unit converters by serial communication. And a plurality of unit converters provided for each group divided into a plurality of groups, and an optical signal distribution means for distributing the transmission signal received from the control means to the unit converters of the group, and for each group An optical signal combining unit configured to combine the return signal of the optical signal returned from the unit converter determined based on the transmission signal for each of the groups, and to transmit to the control unit by serial communication; Prepare. The transmission signal includes a plurality of data corresponding to each of the plurality of unit converters included in the group. Each of the plurality of data includes information for designating the unit converter in charge of reply and information for determining the timing for transmitting the reply signal. The optical signal distribution unit distributes the transmission signal including the plurality of data to each of the plurality of unit converters included in the group. The unit converter recognizes that it is in charge of replying based on information included in the data, and determines the timing for transmitting the reply signal.

  ADVANTAGE OF THE INVENTION According to this invention, the several unit converter can communicate serially and the power converter device with high operation continuity with respect to the abnormality of the line | wire which carries out serial communication can be provided.

1 is a configuration diagram showing a communication circuit of a self-excited power conversion device according to a first embodiment of the present invention. The lineblock diagram showing the composition of the self-excitation power converter concerning a 1st embodiment. The circuit diagram which shows the electric circuit of the cell which concerns on 1st Embodiment. The timing chart which shows the relationship between the transmission signal transmitted from the control apparatus which concerns on 1st Embodiment, and the reply signal returned from each cell. The block diagram which shows the communication circuit of the self-excitation power converter device which concerns on 2nd Embodiment. The block diagram which shows the structure of the self-excitation power converter device which concerns on 2nd Embodiment.

(First embodiment)
FIG. 1 is a configuration diagram showing a communication circuit of a self-excited power conversion device 10 according to the first embodiment of the present invention. FIG. 2 is a configuration diagram illustrating a configuration of the self-excited power conversion device 10 according to the present embodiment. In addition, the same code | symbol is attached | subjected to the same part in drawing, the detailed description is abbreviate | omitted, and a different part is mainly described.

  Self-excited power converter 10 includes control device 1, DC power source 2, six arms 3up, 3um, 3vp, 3vm, 3wp, 3wm, three-phase reactors 4u, 4v, 4w, and three-phase interconnected reactors. 5u, 5v, 5w are provided. Self-excited power conversion device 10 is linked to three-phase AC system 6.

  The six arms 3up to 3wm constitute a power conversion circuit that converts DC power into three-phase AC power. The U phase of the power conversion circuit includes an upper arm (positive side arm) 3up of the U phase and a lower arm (negative side arm) 3um of the U phase. The V phase of the power conversion circuit includes an upper arm (positive side arm) 3 vp of the V phase and a lower arm (negative side arm) 3 vm of the V phase. The W phase of the power conversion circuit includes an upper arm (positive arm) 3wp of the W phase and a lower arm (negative arm) 3wm of the W phase. Each arm 3up-3wm is composed of four cells 111-114, 115-118, 121-124, 125-128, 131-134, 135-138 connected in series. The cells 111 to 114 constitute an upper arm 3up of the U phase. The cells 115 to 118 constitute the U-arm lower arm 3um. The cells 121 to 124 constitute the upper arm 3vp of the V phase. The cells 125 to 128 constitute the lower arm 3 vm of the V phase. The cells 131 to 134 constitute the upper arm 3wp of the W phase. The cells 135 to 138 constitute the lower arm 3wm of the W phase.

  The control device 1 is connected to the arms 3up to 3wm via transmission lines LP1 to LP6 formed in a loop shape. The control device 1 serially communicates data including information such as gate signals with the cells (unit converters) 111 to 138 constituting the arms 3up to 3wm via the transmission lines LP1 to LP6. Control the conversion circuit. The transmission lines LP1 to LP6 are mainly composed of optical fiber cables.

  The DC power supply 2 supplies the generated DC power to a power conversion circuit composed of arms 3up to 3wm. The DC power source 2 is not limited to a device that generates power by itself, but may be a converter or a secondary battery that converts AC power into DC power.

  The U-phase reactor 4u is provided between the U-phase upper arm 3up and the U-phase lower arm 3um. Reactor 4u suppresses the direct current component of the circulating current flowing through U-phase upper arm 3up and U-phase lower arm 3um. An intermediate point of reactor 4u is a U-phase output point of AC power. The intermediate point of reactor 4u is connected to the U phase of AC system 6 via interconnection reactor 5u.

  The V-phase reactor 4v is provided between the V-phase upper arm 3vp and the V-phase lower arm 3vm. Reactor 4v suppresses the direct current component of the circulating current flowing through upper arm 3vp of V phase and lower arm 3vm of V phase. The intermediate point of reactor 4v is the V-phase output point of AC power. An intermediate point of reactor 4v is connected to the V phase of AC system 6 via interconnection reactor 5v.

  W-phase reactor 4w is provided between W-phase upper arm 3wp and W-phase lower arm 3wm. Reactor 4w suppresses the direct current component of the circulating current flowing through upper arm 3wp of W phase and lower arm 3wm of W phase. An intermediate point of reactor 4w is a W-phase output point of AC power. The intermediate point of reactor 4w is connected to the W phase of AC system 6 via interconnection reactor 5w.

  Interconnection reactors 5 u, 5 v, 5 w are reactors provided for system interconnection with AC system 6. Interconnected reactors 5 u, 5 v, 5 w are provided for each phase between the AC output of self-excited power converter 10 and AC system 6. In addition, you may replace the interconnection reactors 5u, 5v, and 5w with an interconnection transformer.

  FIG. 3 is a circuit diagram showing an electric circuit of the cell 100 according to the present embodiment. All the cells 111 to 138 are electric circuits having the same configuration as the cell 100.

  Cell 100 is a double star chopper. The cell 100 is a circuit composed of two switching elements 101 and 102, two antiparallel diodes 103 and 104, and a capacitor 105. The cell 100 is driven by switching the two switching elements 101 and 102 by the gate signal transmitted from the control device 1.

  The two switching elements 101 and 102 are connected in series. Antiparallel diodes 103 and 104 are connected to the two switching elements 101 and 102, respectively. The capacitor 105 is connected in parallel with the two switching elements 101 and 102 connected in series. A connection point between the two switching elements 101 and 102 is a positive terminal of the cell 100. A terminal (emitter) on the negative electrode side of the switching element 102 located on the negative electrode side becomes a negative electrode terminal of the cell 100.

  With reference to FIG. 1, the configuration of a communication circuit in which the arm 3up communicates with the control device 1 will be described. In addition, about the structure of the communication circuit which the other arms 3um-3wm communicate with the control apparatus 1, since it is the same as that of the structure of the arm 3up, description is abbreviate | omitted.

  The arm 3up is connected to the control device 1 through a loop-shaped transmission line LP1 including two transmission lines LP11 and LP12. The arm 3up includes two optical couplers 31r and 31t commonly used by the cells 111 to 114. Each of the cells 111 to 114 constituting the arm 3up includes a pair of light receiving circuits R11, R12, R13, and R14 and light emitting circuits T11, T12, T13, and T14.

  The optical coupler 31r on the receiving side branches the optical signal including the information transmitted from the control device 1, and distributes the branched optical signal to each of the cells 111 to 114. Each of the cells 111 to 114 receives the optical signal distributed from the optical coupler 31r by the light receiving circuits R11 to R14. Each of the cells 111 to 114 extracts information (for example, a gate signal) related to its own cell from the optical signals received by the light receiving circuits R11 to R14.

  In addition, the control device 1 repeatedly designates the cells 111 to 114 in charge of replying in order according to the information included in the optical signal to be transmitted. The designated return cells 111 to 114 include information related to their own cells (for example, analog data such as voltage or current at a predetermined location) in the optical signal, and the light emitting circuits T11 to T14 transmit the information to the optical coupler 31t. Outputs an optical signal.

  When receiving the optical signal from each of the cells 111 to 114, the transmitting optical coupler 31t combines them into one optical signal. The optical coupler 31t transmits (replies) the combined optical signal to the control device 1. Thereby, the optical coupler 31t time-divides one optical signal, and sequentially returns the return signals of the cells 111 to 114 to the control device 1.

  FIG. 4 is a timing chart showing the relationship between the transmission signal S1 transmitted from the control device 1 and the return signals S111, S112, S113, S114 returned from the cells 111, 112, 113, 114. The transmission signal S1 indicates a signal transmitted from the control device 1 to the arm 3up. Reply signals S111 to S114 indicate signals that are returned to the control device 1 in response to reception of the transmission signal S1.

  Here, the case where four data D1-D4 are transmitted with the transmission signal S1 from the control apparatus 1 is demonstrated.

  The four data D1 to D4 transmitted from the control device 1 to the arm 3up via the transmission line LP11 are received by all the cells 111 to 114 constituting the arm 3up. Each of the data D1 to D4 includes information Dt1, Dt2, Dt3, and Dt4 that designates the cells 111 to 114 that are in charge of replying. Here, in each information Dt1 to Dt4, it is assumed that cells 111 to 114 are sequentially specified, respectively.

  When the cell 111 receives the data D1, the cell 111 recognizes that the cell 111 is responsible for a reply from the information Dt1 included in the data D1. The cell 111, which has recognized that it is in charge of replying, transmits data Dr1 including information about itself (analog data, etc.) to the optical coupler 31t as a reply signal S111. The cell 111 determines the timing for transmitting the return signal S111 from the information included in the data D1. Thus, the order of the reply signals S112 to S114 output from the other cells 112 to 114 is not changed.

  Note that the information included in the data D1 is not limited to the information included before transmission from the control device 1. For example, this information is automatically added according to a network protocol or the like such as the time when the data D1 is transmitted from the control device 1 or the time when the cell 111 receives the data D1, or is automatically added during transmission. It may be information.

  Similarly, when the other cells 112 to 114 receive data D2 to D4 that they are responsible for, respectively, send data Dr2 to Dr4 including information about the self as reply signals S112 to S114 to the optical coupler 31t. .

  The optical coupler 31t transmits (replies) reply signals S111 to S114 to the control device 1 via the transmission line LP12 in the order received from the cells 111 to 114. As a result, the arm 3up transmits (replies) the reply signals S111 to S114 to the control device 1 in a time division manner. The control apparatus 1 determines the soundness such as presence or absence of communication abnormality in each of the cells 111 to 114 by sequentially receiving the reply signals S111 to S114 transmitted from the arm 3up.

  Next, for example, the operation of the control device 1 when a communication abnormality occurs between the two optical couplers 31r and 31t passing through the cell 111 (for example, when the cell 111 fails) will be described.

  Even if the control device 1 transmits data in which the cell 111 is designated as a reply person in a state in which the cell 111 has failed, the cell 111 cannot transmit the reply signal S111. Therefore, when the control apparatus 1 does not receive the reply signal S111 within a predetermined time after transmitting data for which the cell 111 is in charge of reply, the control apparatus 1 communicates with the transmission path to which the cell 111 is connected. Judge that an abnormality has occurred. For example, the predetermined time is not limited to a fixed time, and may be until the return signals S112 to S114 from the other cells 112 to 114 are received.

  When the control device 1 determines that a communication abnormality has occurred in the transmission path of the cell 111, the control device 1 excludes the cell 111 and performs control so that the operation of the self-excited power conversion device 10 is continued in the remaining cells 112 to 114. To do. As a result, the three cells 112 to 114 output the AC voltage on the arm 3up.

  According to this embodiment, the optical couplers 31r and 31t are configured to distribute the data from the control device 1 to the cells 111 to 138 for each of the arms 3up to 3wm, so that the control device 1 and the cells 111 to 138 are distributed. Can be equivalently connected so as to communicate one-to-one. Thus, serial communication can be continued even if communication abnormality occurs in some of the cells 111 to 138 in the arms 3up to 3wm. Therefore, the control device 1 can improve the operation continuity of the self-excited power conversion device 10.

  Further, by using the optical couplers 31r and 31t that do not require a power source to transmit data to each of the cells 111 to 138, it is possible to eliminate a communication abnormality caused by the power source.

(Second Embodiment)
FIG. 5 is a configuration diagram showing a communication circuit of the self-excited power conversion device 10A according to the second embodiment of the present invention. FIG. 6 is a configuration diagram showing the configuration of the self-excited power conversion device 10A according to the present embodiment.

  The self-excited power conversion device 10A has a double system configuration consisting of an A system and a B system in the self-excited power conversion device 10 according to the first embodiment shown in FIGS. Other points are the same as in the first embodiment.

  With reference to FIG. 5, the dual configuration of self-excited power converter 10A will be described. Here, the upper arm 3upA of the U phase will be described, but the same applies to the other arms 3umA, 3vpA, 3vmA, 3wpA, and 3wmA.

  The self-excited power conversion device 10A includes two control devices 1a and 1b. Each control device 1a, 1b is equivalent to the control device 1 according to the first embodiment. In either control of the two control devices 1a and 1b, the self-excited power conversion device 10A can be operated and arbitrarily switched. For example, when a failure occurs in either the A system or the B system, the system may be automatically switched to a normal system, or may be configured to be manually switched at an arbitrary timing. Further, when both systems are normal, it may be determined which system operates according to a predetermined priority order.

  The arm 3upA includes two sets of optical couplers 31ra and 31rb on the reception side, optical couplers 31ta and 31tb on the transmission side, and four cells 111A to 114A. Other points are the same as those of the arm 3up according to the first embodiment.

  Each of the cells 111A to 114A includes two sets of light receiving circuits R11a to R14a, R11b to R14b, and light emitting circuits T11a to T14a, T11b to T14b. Other points are the same as those of the cells 111 to 114 according to the first embodiment.

  The configuration of the A system is a loop including a control device 1a, an optical coupler 31ra, a set of light receiving circuits R11a to R14a and light emitting circuits T11a to T14a of each cell 111A to 114A, an optical coupler 31ta, and two transmission lines LP11a and LP12a. Shaped transmission line LP1a.

  The configuration of the B system is a loop including a control device 1b, an optical coupler 31rb, a set of light receiving circuits R11b to R14b and light emitting circuits T11b to T14b of each cell 111A to 114A, an optical coupler 31tb, and two transmission lines LP11b and LP12b. Shaped transmission line LP1b.

  The configurations of the A system and the B system are the same as those described in the first embodiment, the control device 1, the optical coupler 31r, a pair of light receiving circuits R11 to R14 and light emitting circuits T11 to T14 of each of the cells 111 to 114, and light. The configuration is the same as that of the loop-shaped transmission line LP1 including the coupler 31t and the two transmission lines LP11 and LP12. Each configuration of the A system and the B system operates independently, and is configured so that the self-excited power conversion device 10A can operate normally if at least one of the A system or the B system is normal. .

  According to the present embodiment, in addition to the operational effects of the first embodiment, the continuity of operation due to communication abnormality in serial communication can be further improved by using a dual communication circuit. In addition, although the structure of the double system has been described here, it may be configured of a triple system or more.

  In addition, in each embodiment, although the loop-shaped transmission line was constructed | assembled for every arm, it is not restricted to this. The cells 111 to 138 may be grouped in any way to construct a loop-shaped transmission path, and one group may span a plurality of arms.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

  DESCRIPTION OF SYMBOLS 1 ... Control apparatus, 3up ... Arm, 10 ... Self-excited power converter, 31r, 31t ... Optical coupler, 111-114 ... Cell, LP1, LP11, LP12 ... Transmission path, R11-R14 ... Light receiving circuit, T11-T14 ... Light emitting circuit.

Claims (6)

A plurality of unit converters constituting a power conversion circuit;
Control means for transmitting a transmission signal of an optical signal including information for controlling the plurality of unit converters by serial communication;
The plurality of unit converters are provided for each group divided into a plurality, and an optical signal distribution unit that distributes the transmission signal received from the control unit to the unit converters of the group;
Optical signal synthesis provided for each group, which synthesizes a reply signal of an optical signal returned from the unit converter determined based on the transmission signal for each group, and transmits the signal to the control means by serial communication Means ,
Equipped with a,
The transmission signal includes a plurality of data corresponding to each of the plurality of unit converters included in the group,
Each of the plurality of data includes information specifying the unit converter in charge of reply, and information determining timing for transmitting the reply signal,
The optical signal distribution means distributes the transmission signal including the plurality of data to each of the plurality of unit converters included in the group,
The power converter according to claim 1, wherein the unit converter recognizes that it is in charge of a reply based on information included in the data and determines a timing for transmitting the reply signal . The power conversion device according to claim 1, wherein the group is divided for each arm configuring the power conversion circuit. 3. The power conversion apparatus according to claim 1, wherein the optical signal distribution unit and the optical signal synthesis unit are optical couplers that do not require a power source. A plurality of the control means,
4. The power conversion apparatus according to claim 1, wherein the control unit controls the plurality of unit converters. 5. A control device for controlling the configured power converter in units converter multiple,
Control means for transmitting a transmission signal of an optical signal including information for controlling the plurality of unit converters by serial communication;
The plurality of unit converters are provided for each group divided into a plurality, and an optical signal distribution unit that distributes the transmission signal received from the control unit to the unit converters of the group;
An optical signal combining unit that is provided for each group, combines a return signal of an optical signal returned from the unit converter determined based on the transmission signal, for each group, and transmits the signal to the control unit by serial communication. and,
Equipped with a,
The transmission signal includes a plurality of data corresponding to each of the plurality of unit converters included in the group,
Each of the plurality of data includes information specifying the unit converter in charge of reply, and information determining timing for transmitting the reply signal,
The optical signal distribution means distributes the transmission signal including the plurality of data to each of the plurality of unit converters included in the group,
The unit converter recognizes that it is responsible for a reply based on information included in the data and determines a timing for transmitting the reply signal. apparatus. A control method for controlling a power conversion device including a plurality of unit converters,
A transmission signal of an optical signal including information for controlling the plurality of unit converters is transmitted from the control unit by serial communication,
The optical signal distribution means provided for each of the plurality of unit converters divided into a plurality of groups, distributes the transmission signal to the unit converters of the group,
For each said group, said reply signal of the optical signal returned from said unit converters, which are determined based on the transmission signal by combining each of the groups, viewed contains a transmitting serial communication to the controller,
The transmission signal includes a plurality of data corresponding to each of the plurality of unit converters included in the group,
Each of the plurality of data includes information specifying the unit converter in charge of reply, and information determining timing for transmitting the reply signal,
The optical signal distribution means distributes the transmission signal including the plurality of data to each of the plurality of unit converters included in the group,
Based on the information included in the data, the unit converter recognizes that it is responsible for a reply and determines the timing for transmitting the reply signal
A method for controlling a power conversion device.

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