POWER CONVERSION DEVICE AND METHOD FOR CONTROLLING POWER CONVERSION DEVICE

Abstract

Provided are: an electric power conversion device that rapidly transmits current values of a plurality of inverters; and a control method for the electric power conversion device. This electric power conversion device comprises a main controller, a plurality of subcontrollers, and a relay unit. The main controller generates and outputs a control command that is a target value for controlling electric power conversion performed by a plurality of electric power conversion units on the basis of state quantity information relating to a state quantity of each of the plurality of electric power conversion units that receive electric power with respect to a load. The subcontrollers are provided, respectively, to the power conversion units to control the power conversion units on the basis of the control command, and to acquire and output the state quantities. The relay unit: generates the state quantity information by performing information compression on the state quantities output by the plurality of subcontrollers; and transmits the state quantity information to the main controller side.

Description

[Technical field]

[0001] The disclosed embodiments relate to a power conversion device and a control method for the power conversion device. [Background technology]

[0002] 2. Description of the Related Art Conventionally, a system is known in which a motor or the like is driven by a plurality of inverters.

[0003] For example, a system has been proposed in which multiple inverters and auxiliary power supplies that individually supply power to the inverters are connected in parallel, and the current of each inverter is feedback-controlled based on the sum of the currents of the respective inverters (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-130599 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the above-mentioned conventional technology, the sum and average of the output current vectors representing the currents of the inverters are calculated by a central transmission control unit and fed back to each inverter. In this case, as the number of inverters increases, there is a problem that it takes time to transmit the output current vectors.

[0006] An object of one aspect of the embodiments is to provide a power conversion device and a control method for the power conversion device that perform high-speed transmission of state quantities of a plurality of inverters. [Means for solving the problem]

[0007] A power conversion device according to one aspect of the embodiment includes a main controller, a plurality of sub-controllers, and a relay unit. The main controller generates and outputs a control command that is a target value for controlling power conversion performed by a plurality of power conversion units based on state quantity information related to state quantities for each of the plurality of power conversion units that receive power to a load. A sub-controller is disposed for each of the power conversion units, controls the power conversion unit based on the control command, and acquires and outputs the state quantities. The relay unit compresses the state quantities output by the plurality of sub-controllers to generate the state quantity information, and transmits the state quantity information to the main controller.

[0008] In addition, a control method for a power conversion device of one aspect of an embodiment includes generating and outputting a control command which is a target value for controlling the power conversion performed by a plurality of power conversion units using state quantity information regarding a state quantity of each of a plurality of power conversion units that supply power to a load, controlling the power conversion units based on the control command for each of the power conversion units and acquiring and outputting the state quantities, and compressing the outputted plurality of state quantities to generate the state quantity information, and using it to generate the control command. Effect of the Invention

[0009] According to one aspect of the embodiment, it is possible to provide a power conversion device and a control method for a power conversion device that can transmit current values ​​of a plurality of inverters at high speed. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a power conversion device according to a first embodiment. [Diagram 2] FIG. 2 is a diagram illustrating an example of the configuration of the sub-controller according to the first embodiment. [Diagram 3] FIG. 3 is a diagram illustrating an example of the configuration of the main controller according to the first embodiment. [Figure 4] FIG. 4 is a diagram illustrating an example of the configuration of the relay controller according to the first embodiment. [Figure 5A] FIG. 5A is a diagram illustrating an example of a configuration of communication data according to the first embodiment. [Figure 5B] FIG. 5B is a diagram showing an example of the status. [Figure 6] FIG. 6 is a diagram illustrating an example of transmission of communication data according to the first embodiment. [Figure 7A] FIG. 7A is a diagram illustrating an example of a control method of the main controller according to the first embodiment. [Figure 7B] FIG. 7B is a diagram illustrating an example of a control method of the relay controller according to the first embodiment. [Figure 7C] FIG. 7C is a diagram illustrating an example of a control method of the sub-controller according to the first embodiment. [Figure 8] FIG. 8 is a diagram illustrating an example of the configuration of a power conversion device according to the second embodiment. [Figure 9] FIG. 9 is a diagram illustrating an example of the configuration of a sub-controller according to the second embodiment. [Figure 10] FIG. 10 is a diagram illustrating another configuration example of the power conversion device according to the second embodiment. [Figure 11A] FIG. 11A is a diagram illustrating an example of the configuration of a relay controller according to the third embodiment. [Figure 11B] FIG. 11B is a diagram illustrating an example of the configuration of the main controller according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments described below. Note that in each of the following embodiments, the same components are designated by the same reference numerals, and duplicated descriptions will be omitted.

[0012] (First embodiment) [Power conversion device configuration] FIG. 1 is a diagram showing a configuration example of a power conversion device according to a first embodiment. The figure is a block diagram showing a configuration example of a power conversion device 1. This power conversion device 1 controls a plurality of power conversion units (power conversion units 4 described later) that supply power to a load such as a motor. In addition, the power conversion device 1 performs the above-mentioned control under the control of a higher-level control device. This higher-level control device corresponds to, for example, a control device that controls the entire system.

[0013] The power conversion device 1 includes a main controller 10, a relay unit 20, and a plurality of sub-controllers 40. The power conversion device 1 in the figure shows an example including eight sub-controllers (sub-controller 40a to sub-controller 40h).

[0014] The main controller 10 is connected to a higher-level control device via a communication path 51. The main controller 10 is also connected to the relay unit 20 via a communication path 52. In the example shown in the figure, the main controller 10 is connected to the relay unit 20 via communication paths 52a and 52b.

[0015] The relay unit 20 is connected to the sub-controller 40 via a communication path 54. In the example shown in the figure, the relay unit 20 is connected to the sub-controller 40a to the sub-controller 40h via a plurality of communication paths 54a and 54b.

[0016] As shown in the figure, the relay unit 20 has a relay controller 30. The relay unit 20 in the figure shows an example in which the relay unit 20 has a plurality of relay controllers 30 connected in a tree configuration. The relay unit 20 in the figure has six relay controllers 30 connected in a two-stage tree configuration.

[0017] The relay controller 30 is connected to a device on the main controller 10 side by one communication path, and can be connected to a plurality of devices on the sub-controller 40 side by respective communication paths. This allows the relay controllers 30 to be connected in a tree configuration. The relay controller 30 in the figure shows an example in which it is connected to two devices on the sub-controller 40 side.

[0018] Specifically, the first stage relay controller 30a of the relay unit 20 is connected to the main controller 10 via a communication path 52a, and is connected to the relay controllers 30c and 30d via communication paths 53a and 53b, respectively. The first stage relay controller 30b of the relay unit 20 is connected in the same manner.

[0019] The second-stage relay controller 30c of the relay unit 20 is connected to the relay controller 30a via the communication path 53a, and is connected to the sub-controllers 40a and 40b via communication paths 54a and 54b, respectively. The second-stage relay controller 30d of the relay unit 20 is connected in the same manner.

[0020] In addition, the second stage relay controller 30e of the relay unit 20 is connected to the above-mentioned relay controller 30b via the above-mentioned communication path 53a, and is also connected to the sub-controller 40e and the sub-controller 40f via the communication paths 54a and 54b, respectively. The second stage relay controller 30f of the relay unit 20 is connected in the same manner.

[0021] A communication path for serial communication can be used as the communication paths 51, 52, 53, and 54. In this case, the communication path 52 etc. can be configured as a full-duplex communication path or a half-duplex communication path.

[0022] [Sub-controller configuration] 2 is a diagram showing an example of the configuration of the sub-controller of the first embodiment. The figure is a block diagram showing an example of the configuration of the sub-controller 40. In addition to the sub-controller 40, the figure also shows the motor 2, the power conversion unit 4, and the sensor unit 3. The power conversion unit 4 in the figure supplies power to the motor 2. The sub-controller 40 controls this power conversion unit 4.

[0023] Note that this figure shows an example in which multiple power conversion units 4a-4h connected in parallel, similar to Fig. 1, are connected to a motor 2. In this figure, one motor 2 is driven by multiple power conversion units 4a-4h. Sub-controllers 40a-40h and sensor units 3a-3h are provided for each power conversion unit 4a-4h.

[0024] For example, a three-phase induction motor can be applied to the motor 2. The power conversion unit 4 can use a circuit in which a plurality of switch elements are connected in a three-phase bridge. The power conversion unit 4 is connected to the motor 2 via a U-phase line, a V-phase line, and a W-phase line, and converts DC power supplied from a power supply unit (not shown) into AC power and supplies it to the motor 2. The AC power supplied to the motor 2 is controlled by PWM (Pulse Width Modulation) to adjust the power. This controls the rotation speed and torque of the motor 2. The PWM control is performed by a sub-controller 40, and the power conversion unit 4 supplies AC power to the motor 2 according to a PWM control signal based on the PWM control from the sub-controller 40.

[0025] The sub-controller 40 detects the state quantity of the motor 2. As this state quantity, the current value flowing through the motor 2 is assumed. In this case, the control command corresponds to a voltage command. The sub-controller 40 receives the voltage command via the communication path 54, generates a PWM control signal corresponding to the voltage command, and outputs the PWM control signal to the power conversion unit 4. The sub-controller 40 may correct the voltage command based on the detected current value flowing through the motor 2, and generate a PWM control signal corresponding to the corrected voltage command. For example, the sub-controller 40 may receive the current command used to generate the voltage command together with the voltage command via the communication path 54, and correct the voltage command based on the current command and the detected current value flowing through the motor 2. This PWM control signal is input to a switch element of the power conversion unit 4, for example, a gate terminal of an IGBT. In this way, the sub-controller 40 drives the switch element of the power conversion unit 4 by a PWM signal corresponding to the voltage command, causing the power conversion unit 4 to generate an output voltage corresponding to the voltage command. As a result, the sub-controller 40 controls the power conversion in the power conversion unit 4 so that the required power is supplied to the motor 2. The voltage command is generated by the main controller 10.

[0026] The line currents of the U-phase wire, the V-phase wire, and the W-phase wire of the power conversion unit 4 can be detected by the sensor unit 3. The sensor unit 3 is arranged for each power conversion unit 4 and can be composed of three current sensors corresponding to the U-phase wire, the V-phase wire, and the W-phase wire, respectively. The current sensors can be sensors using a current transformer or a Hall element. These current sensors output an analog signal according to the line current. The current detected by the sensor unit 3 is transmitted to the sub-controller 40 by a signal line Iu, a signal line Iv, and a signal line Iw corresponding to the U-phase wire, the V-phase wire, and the W-phase wire, respectively. Note that current sensors do not need to be provided for all three phases of the U-phase wire, the V-phase wire, and the W-phase wire. It is possible to provide current sensors for only two phases on the premise that the sum of the currents of the three phases is zero, and the currents of the remaining phases can be calculated from the two line currents detected by the current sensors.

[0027] The sub-controller 40 in the figure includes a host communication port 41, a control unit 42, a drive unit 43, and a current detection unit 44.

[0028] The upper communication port 41 communicates with the relay controller 30, which is a higher-level device. This upper communication port 41 is connected to the relay controller 30 via a communication path 54. The upper communication port 41 receives control commands and the like transmitted by the relay controller 30, and transmits state quantities and statuses to the relay controller 30.

[0029] The control unit 42 controls at least data transmission and reception in the sub-controller 40. Specifically, the control unit 42 outputs a control command received from the upper communication port 41 via the communication path 54 to the drive unit 43, and transmits a current value detected by the current detection unit 44 as a state quantity from the upper communication port 41 via the communication path 54. The control unit 42 also generates a status and transmits it from the upper communication port 41 via the communication path 54.

[0030] The drive unit 43 drives the power conversion unit 4. The drive unit 43 generates a control signal for the power conversion unit 4 based on a control command output from the control unit 42. For example, the drive unit 43 compares the control command with a triangular wave to generate a PWM control signal and outputs the PWM control signal to the power conversion unit 4. Alternatively, the control unit 42 may generate the PWM control signal by a space vector control method. Furthermore, the control unit 42 may take the current value detected by the current detection unit 44 as a state quantity, correct the control command based on this state quantity, and generate a PWM control signal based on the corrected control command.

[0031] The current detection unit 44 outputs the current value output from the sensor unit 3 as a state quantity to the drive unit 43 and the control unit 42. The current detection unit 44 includes an analog-to-digital converter and converts the analog current value output from the sensor unit 3 into a digital current value and outputs the digital current value to the drive unit 43 and the control unit 42.

[0032] In addition, as long as the control unit 42, drive unit 43 and current detection unit 44 are capable of detecting state quantities and transmitting and receiving the detected state quantities from the upper communication port 41, the configurations of these units and the processing contents of each unit may differ depending on the sub-controllers 40a-40h.

[0033] [Main controller configuration] 3 is a diagram showing an example of the configuration of the main controller of the first embodiment. The figure is a block diagram showing an example of the configuration of the main controller 10. The main controller 10 in the figure includes an upper communication port 11, a control unit 12, and lower communication ports 13 and 14.

[0034] The host communication port 11 communicates with a host control device. The host communication port 11 is connected to a communication path 51.

[0035] The lower communication ports 13 and 14 communicate with devices on the sub-controller 40 side, which is a lower device. The lower communication ports 13 and 14 are connected to the relay controller 30 via different communication paths 52. The lower communication ports 13 and 14 transmit control commands and receive state quantities and statuses from the relay controller 30.

[0036] The control unit 12 at least generates control commands and controls data transmission and reception in the main controller 10. Specifically, the control unit 12 generates control commands for the power conversion units 4 based on state quantities for each power conversion unit 4 driven by the sub-controller 40. For example, the control unit 12 acquires a control target received from a higher-level control device via a communication path 51 or input from an IO device (not shown) attached to the main controller 10. The control target corresponds to, for example, a speed command or a torque command for the motor 2. The control unit 12 generates a target value for the state quantity from this control target. A current command is assumed as the target value for this state quantity.

[0037] Based on the sum of a plurality of current values, which are a plurality of state quantities detected by the plurality of sub-controllers 40, and a current command, a control command is generated, which is a target value for controlling the power conversion performed by the power conversion unit 4. The control command corresponds to, for example, a voltage command. The generation of the control command includes, for example, the generation of a voltage target based on a current command according to vector control of an AC motor, and the generation of a voltage command by correcting the voltage target based on a difference value between the current command and the sum of a plurality of current values. The control unit 12 performs feedback control by outputting a voltage command, which is this control command, to the sub-controller 40 side. The control command of the drive unit 43 is updated by the control command generated by the main controller 10 and transmitted via the relay controller 30.

[0038] Moreover, state quantities are input to the lower communication ports 13 and 14 from the respective relay controllers 30. The control section 12 adds these state quantities together to generate the sum of the above-mentioned state quantities.

[0039] A relay controller 30 is disposed between the main controller 10 and the sub-controller 40. The state quantities from the sub-controller 40 are transmitted to the main controller 10 via the relay controller 30. At this time, the relay controller 30 can generate state quantity information by compressing a plurality of state quantities, and transmit the information to the main controller 10. As described later, this information compression can be performed by adding the state quantities. Furthermore, when state quantity information is transmitted from a lower relay controller 30, the relay controller 30 further compresses the state quantity information. This can be performed by adding the state quantity information. The addition of these state quantities and state quantity information is an example of information compression in the relay controller 30.

[0040] In this case, the main controller 10 generates a control command based on state quantity information relating to the state quantities. Specifically, the main controller 10 can generate a sum of state quantities by adding up state quantity information from a plurality of relay controllers 30. The state quantity information will be described in detail later.

[0041] [Relay controller configuration] 4 is a diagram showing a configuration example of a relay controller of the first embodiment. The figure is a block diagram showing a configuration example of a relay controller 30. The relay controller 30 in the figure includes an upper communication port 31, a control unit 32, and lower communication ports 33 and 34.

[0042] The upper communication port 31 communicates with either the main controller 10, which is a higher-level device, or the relay controller 30 on the side of the main controller 10. The relay controller 30 in the figure shows an example connected to the relay controller 30 on the side of the main controller 10. The upper communication port 31 in the figure is connected to a communication path 53. The upper communication port 31 transmits state quantity information and status, and receives control commands.

[0043] The lower communication ports 33 and 34 communicate with either the sub-controller 40, which is a lower device, or the relay controller 30 on the side of the sub-controller 40. The lower communication ports 33 and 34 in the figure are connected to the sub-controller 40 via different communication paths 54. The lower communication ports 33 and 34 transmit control commands and receive either state quantities or state quantity information and status.

[0044] The control unit 32 at least generates state quantity information and controls data transmission and reception in the relay controller 30. Specifically, the control unit 32 transmits a control command from the main controller 10 side received by the upper communication port 31 to the sub-controller 40 side via the lower communication ports 33 and 34. The control unit 32 also compresses information. When the lower communication ports 33 and 34 are connected to the sub-controller 40, the control unit 32 compresses the received state quantity to generate state quantity information. When the lower communication ports 33 and 34 are connected to the relay controller 30, the control unit 32 further compresses the received state quantity information to generate new state quantity information.

[0045] The control unit 32 can compress information by adding up multiple state quantities input to itself. In this case, the state quantity information generated by the information compression corresponds to the sum of the multiple state quantities input to itself. The control unit 32 can also compress the state quantity information by adding up the multiple state quantity information input to itself to generate new state quantity information.

[0046] Furthermore, the control unit 32 can also aggregate the statuses received by the lower communication ports 33 and 34 to generate a new status and transmit it from the upper communication port 31. Details of the status aggregation will be described later.

[0047] [Data Configuration] 5A is a diagram showing an example of communication data in the first embodiment. The diagram shows an example of communication data 100 transmitted through communication paths 52-54. The communication data 100 shows an example corresponding to serial communication. The communication data 100 includes a flag 101, data 110, a CRC 102, and a flag 103.

[0048] Flag 101 is data indicating the beginning of communication data. Flag 103 is data indicating the end of communication data. Data 110 is the main data transmitted by communication data 100. CRC 102 is a code for detecting data errors by a Cyclic Redundancy Check (CRC).

[0049] The data 110 in the communication data 100 transmitted from the main controller 10 includes a control command 111. The data 110 may also include a command indicating an instruction to the sub-controller 40, etc., the address of the sub-controller 40, etc.

[0050] The data 110 in the communication data 100 when transmitted from the sub-controller 40 has a state quantity 121 and a status 130. The state quantity 121 corresponds to the current value of the power conversion unit 4 for each sub-controller 40. In addition, in the case of the data 110 in the communication data 100 transmitted from the relay controller 30, state quantity information is placed in place of the state quantity 121.

[0051] FIG. 5B is a diagram showing an example of a status. This figure shows an example of a status 130. The status 130 in this figure shows an example that is composed of a plurality of status bits. The status 130 in this figure includes status bits of an error status 131 and an operable status 132. The error status 131 is a status bit that indicates a state in which an error has occurred in the sub-controller 40 or the like. The error status 131 can be set to a value of "1" when an error has occurred, for example. The error status 131 can be a plurality of status bits that indicate a state in which an error has occurred for each of a plurality of error items. The operable status 132 is a status bit that indicates a state in which the sub-controller 40 is operable. The operable status 132 can be set to a value of "1" when the sub-controller 40 is operable, for example.

[0052] As described above, the relay controller 30 aggregates the two statuses received by the downstream communication ports 33 and 34 to generate a new status. This aggregation can be performed as follows. For the error status 131, a logical OR operation is performed on the error status 131 of each of the two statuses 130 to generate a new 1-bit error status 131. This makes it possible to transmit the state of the error to the main controller 10 when at least one of the error statuses 131 of the two statuses 130 is in an error state (value "1").

[0053] On the other hand, for the ready status 132, a logical AND operation is performed on the ready status 132 of each of the two statuses 130 to generate a new one-bit ready status 132. As a result, when the ready status 132 of both statuses 130 is in a ready state (value "1"), the ready state can be transmitted to the main controller 10. In this way, an aggregation method according to the status bit can be applied.

[0054] [Transmission of communication data] Fig. 6 is a diagram showing an example of communication data transmission in the first embodiment. The diagram shows the transmission of state quantities from the sub-controller 40 to the main controller 10 shown in Fig. 1, and the transmission of state quantity commands from the main controller 10 to the sub-controller 40. Furthermore, the diagram shows the manner in which state quantities and the like are transmitted between the relay controllers 30. Note that the diagram shows only the main controller 10, the relay controllers 30a, 30c, and 30d, and the sub-controllers 40a-40d of Fig. 1.

[0055] In the figure, "sub-controller 40a", "sub-controller 40b", and "relay controller 30c" represent communication data transmitted and received by sub-controller 40a, sub-controller 40b, and relay controller 30c, respectively. Also, "sub-controller 40c", "sub-controller 40d", and "relay controller 30d" represent communication data transmitted and received by sub-controller 40c, sub-controller 40d, and relay controller 30d, respectively. Also, "relay controller 30a" represents communication data transmitted and received by relay controller 30a.

[0056] Furthermore, T1, T2, T3, T4, T5, and T6 represent communication periods. T1, T2, and T3 are communication periods for transmitting state quantities from the sub-controller 40 to the main controller 10, and T4, T5, and T6 are communication periods for transmitting state quantity commands and the like from the main controller 10 to the sub-controller 40. In addition, in the figure, it is assumed that the state quantity is a current value, and the state quantity command is a voltage command.

[0057] First, the sub-controllers 40a-40d detect current values ​​corresponding to the state quantities of the power conversion unit 4. Ia, Ib, Ic, and Id in the figure represent the detected current values ​​of the sub-controllers 40a, 40b, 40c, and 40d, respectively.

[0058] Next, in a communication period T1, the sub-controllers 40a-40d transmit the current values ​​via the communication path 54. The sub-controllers 40a and 40b transmit the current values ​​to the relay controller 30c. The sub-controllers 40c and 40d transmit the current values ​​to the relay controller 30d.

[0059] Next, in the communication period T2, the relay controller 30c adds the transmitted current values ​​Ia and Ib (addition 1) to generate a current sum Im1. Also, the relay controller 30d adds the transmitted current values ​​Ic and Id (addition 1) to generate a current sum Im2. Next, the relay controller 30c and the relay controller 30d transmit the current sums Im1 and Im2 to the relay controller 30a via the communication path 53, respectively.

[0060] Next, in a communication period T3, the relay controller 30a adds the transmitted current sums Im1 and Im2 (addition 2) to generate a current sum Im3. Next, the relay controller 30a transmits the current sum Im3 to the main controller 10 via the communication path 52.

[0061] In addition, the addition 1 in the figure can be performed in a time shorter than the transmission time of the current sum Im1. Therefore, the communication period T2 can be set to the same length as the communication period T1. This is also true for the communication period T3. The main controller 10, the relay controllers 30b, 30e, and 30f, and the sub-controllers 40e-40h also transmit state quantities in the communication periods T1, T2, and T3 in the same manner.

[0062] In this way, the relay controller 30 adds up a plurality of state quantities and generates and transmits state quantity information corresponding to a partial sum of the state quantities relative to the total sum of all the state quantities, thereby reducing the amount of data transmitted through the communication paths 52 and 53. This makes it possible to reduce the time required for each communication period (communication periods T1, T2, T3) required for transmitting the state quantities, and shorten the communication time required for transmitting all the state quantities.

[0063] Next, the main controller 10 generates a voltage command corresponding to the state quantity command. VC in the figure represents the voltage command generated by the main controller 10.

[0064] Next, in a communication period T4, the main controller 10 transmits a voltage command VC via the communication path 52 to the relay controller 30a.

[0065] Next, in a communication period T5, the relay controller 30a transmits a voltage command VC via the communication path 53 to the relay controllers 30c and 30d.

[0066] Next, in a communication period T6, the relay controllers 30c and 30d transmit a voltage command VC to the sub-controllers 40a-40d via the communication path 54. The relay controller 30c transmits the voltage command VC to the sub-controllers 40a and 40b. The relay controller 30d transmits the voltage command VC to the sub-controllers 40c and 40d. Note that the main controller 10, the relay controllers 30b, 30e, and 30f, and the sub-controllers 40e-40h also transmit control commands in the same manner in the communication periods T4, T5, and T6.

[0067] In transmitting the state quantity command, the state quantity command (voltage command) generated by the main controller 10 is transmitted (distributed) to the sub-controller 40 via the relay controller 30.

[0068] [Method of controlling a current conversion device] FIG. 7A is a diagram showing an example of a control method of the main controller of the first embodiment. This figure is a flowchart showing an example of the control method, taking the main controller 10 shown in FIG. 3 as an example. First, the main controller 10 acquires a control target (step S101). Next, the main controller 10 acquires state quantity information (step S102). This can be done by acquiring state quantity information received by the lower communication ports 13 and 14. Next, the main controller 10 generates a control command (step S103). Next, the main controller 10 sends out the generated control command (step S104). Next, the main controller 10 waits until the start of a control cycle (step S106, No), and when the control cycle starts (step S106, Yes), it proceeds to the process of step S101. Note that a state quantity input start command of the sub-controller 40 described later can be applied to start the control cycle.

[0069] FIG. 7B is a diagram showing an example of a control method of the relay controller of the first embodiment. The figure is a flowchart showing an example of the control method, taking the relay controller 30 in FIG. 4 as an example. First, the relay controller 30 judges whether or not a control command has been acquired (step S111). This can be done based on whether or not a control command has been received from a device on the main controller 10 side in the tree connection. If a control command has been acquired (step S111, Yes), the acquired control command is sent (step S112). This can be done by sending the control command to a device on the sub-controller 40 side in the tree connection. Then, the process returns to step S111. On the other hand, if a control command has not been acquired in step S111 (step S111, No), the process proceeds to step S113.

[0070] In step S113, the relay controller 30 judges whether or not the state information or state quantity information has been acquired (step S113). This can be done based on whether or not the state information or state quantity information has been received from the device on the sub-controller 40 side in the tree connection. If the state information or state quantity information has been acquired (step S113, Yes), the relay controller 30 generates state information based on the state information or state quantity information (step S114). Next, the generated state information is sent (step S115). This can be done by sending the generated state information to the device on the main controller 10 side in the tree connection. Then, the process returns to step S111. On the other hand, if the state information or state quantity information has not been acquired in step S113 (step S113, No), the process returns to step S111.

[0071] FIG. 7C is a diagram showing an example of a control method of the sub-controller of the first embodiment. The figure is a flowchart showing an example of the control method, taking the sub-controller 40 shown in FIG. 2 as an example. First, the sub-controller 40 outputs a state quantity input start command (step S121). This corresponds to, for example, outputting an AD conversion start command of the state quantity (current value) to the current detection unit 44 described in FIG. 2. Next, the sub-controller 40 acquires a control command (step S122). This can be performed by acquiring the control command received by the upper communication port 41. Next, the sub-controller 40 acquires a state quantity (step S123). This can be performed by the control unit 42 acquiring the state quantity (current value) detected by the current detection unit 44.

[0072] Next, a control signal for the power conversion unit 4 is generated (step S124). This can be done by the drive unit 43 generating the control signal based on the control of the control unit 42. Next, the sub-controller 40 sends out the control signal (step S125). As a result, the generated control signal is sent to the power conversion unit 4. Next, the sub-controller 40 sends out a state quantity (step S126). This can be done by sending the generated state quantity to a device on the main controller 10 side in the tree connection. Next, the sub-controller 40 waits until the end of the control period (step S127, No), and when the control period ends (step S127, Yes), proceeds to the processing of step S121.

[0073] It should be noted that the control period referred to here may be a control period longer than the time required for the sub-controller 40 to output a state quantity input start command, for the state quantity acquired (detected) by the sub-controller 40 to be transmitted to the main controller 10 via the relay controller 30, for the main controller 10 to generate a control command based on the state quantity received, for the control command to be transmitted to the sub-controller 40 via the relay controller 30, and for the sub-controller 40 to generate a control signal based on the control command received and send it to the power conversion unit 4.

[0074] The control period may be longer than the processing time of the controller having the longest processing time among the sub-controller 40, the relay controller 30, and the main controller 10. In this case, the sub-controller 40, the relay controller 30, and the main controller 10 simultaneously perform the processing shown in the flow charts of FIG. 7C, FIG. 7B, and FIG. 7A in each control period. In this case, if the number of stages of the relay controller 30 is j, the processing is performed in (2j+2) times the control period until the sub-controller 40 detects the state quantity, generates a control command based on this state quantity, and sends a control signal based on this control command to the power conversion unit 4. However, in this case, the state quantity, the control command, and the control signal are updated every control period.

[0075] In this way, the relay controller 30 compresses multiple state quantities and transmits the state quantity information while generating it, thereby reducing the amount of data transmitted to the main controller 10 and enabling the state quantities to be transmitted at high speed.

[0076] Second Embodiment [Power conversion device configuration] Fig. 8 is a diagram showing a configuration example of a power conversion device according to the second embodiment. The diagram shows a configuration example of a relay controller 30 and a sub-controller 40 in the lowest stage of the relay unit 20 in the power conversion device 1. The relay controller 30 in the diagram differs from the power conversion device 1 in Fig. 1 in that a plurality of sub-controllers 40 are connected to it.

[0077] The relay controller 30 in the figure shows an example in which three sub-controllers 40 are connected in series to communication paths 54a and 54b connected to the lower communication ports 33 and 34, respectively. Sub-controllers 40i, 40j, and 40k are connected to the communication path 54a, and sub-controllers 40l, 40m, and 40n are connected to the communication path 54b. The sub-controllers 40i and 40j are connected by a communication path 55a, and the sub-controllers 40j and 40k are connected by a communication path 55c. The sub-controllers 40l and 40m are connected by a communication path 55b, and the sub-controllers 40m and 40n are connected by a communication path 55d. The communication paths 55a, 55b, 55c, and 55d can be communication paths that perform serial communication in the same way as the communication path 54a.

[0078] [Sub-controller configuration] Fig. 9 is a diagram showing an example of the configuration of a sub-controller according to the second embodiment. The figure is a block diagram showing an example of the configuration of a sub-controller 40. The sub-controller 40 in the figure differs from the sub-controller 40 in Fig. 2 in that it further includes a lower communication port 45.

[0079] The lower communication port 45 communicates with the sub-controller 40, which is a lower device. This lower communication port 45 is connected to other sub-controllers 40 via a communication path 55.

[0080] The control unit 42 in the figure receives control commands via the upper communication port 41 and transmits the control commands to other sub-controllers 40 via the lower communication port 45. The control unit 42 also receives state quantities via the lower communication port 45 and transmits the state quantities to the relay controller 30 or other sub-controllers 40 via the upper communication port 41.

[0081] A plurality of sub-controllers 40 connected in series transmit the state quantities detected by themselves to a higher-level device (the relay controller 30 or other sub-controllers 40) and relay the state quantities of the lower-level sub-controllers 40.

[0082] In this embodiment, each sub-controller 40 may add the state quantity or state quantity information received from the lower sub-controller 40 to the state quantity detected by itself to create new state quantity information and transmit it to the higher-level sub-controller 40 or relay controller 30.

[0083] [Other configurations of power conversion device] Fig. 10 is a diagram showing another configuration example of the power conversion device of the second embodiment. The power conversion device 1 in this figure differs from the power conversion device 1 in Fig. 8 in that a plurality of sub-controllers 40 are bus-connected.

[0084] The sub-controllers 40i, 40j, and 40k in the figure are commonly connected by a bus 56a, and the sub-controllers 40l, 40m, and 40n are commonly connected by a bus 56b. The buses 56a and 56b are also connected to the lower communication ports 33 and 34 of the relay controller 30, respectively.

[0085] In this configuration, each sub-controller occupies the bus in a time-sharing manner and transmits a state quantity to the relay controller 30. For example, in the bus 56a, the sub-controller 40i transmits a state quantity to the relay controller 30 in the first communication period, the sub-controller 40j transmits a state quantity to the relay controller 30 in the next communication period, and the sub-controller 40k transmits a state quantity to the relay controller 30 in the next communication period.

[0086] In this way, by connecting the sub-controllers 40 in series, a plurality of sub-controllers 40 can be connected to the last-stage relay controller 30 of the relay section 20. This allows for flexibility in the arrangement of the sub-controllers 40 connected to the power conversion device 1. In addition, the sub-controllers 40 can be easily expanded.

[0087] (Third embodiment) [Relay controller configuration] 11A is a diagram showing a configuration example of a relay controller of the third embodiment. The figure is a block diagram showing a configuration example of a relay controller 30. The relay controller 30 of the third embodiment is different from the relay controller 30 of FIG. 4 in that it has three or more lower communication ports 33. The relay controller 30 of the figure has four lower communication ports, namely, lower communication ports 33, 34, 35, and 36. The lower communication ports 33, 34, 35, and 36 are connected to another relay controller 30 or a sub-controller 40 via a communication path 54.

[0088] The control unit 32 transmits the control command from the main controller 10 side received by the upper communication port 31 to the sub-controller 40 side via the lower communication ports 33, 34, 35, and 36. In addition, the control unit 32 compresses the state quantities and state quantity information received by the lower communication ports 33, 34, 35, and 36, and causes the upper communication port 31 to transmit the compressed state quantity information.

[0089] In this way, by providing the relay controller 30 with three or more downstream communication ports 33, it is possible to connect more downstream devices.

[0090] 8, in this embodiment, it is also possible to connect a plurality of sub-controllers 40 to the respective lower communication ports 33 of the relay controller 30 in the lowest stage of the relay unit 20. In this case, the sub-controllers 40 connected to these lower communication ports 33 can be regarded as constituting one group. Here, assuming that the main controller 10 also has the same number of communication ports 13 as the relay controllers 30, and that the number of lower communication ports 33 of the relay controller 30 is i and the number of stages of the relay controllers 30 in the relay unit 20 is j, the sub-controllers 40 can be divided into n groups as shown in the following formula. i j-1 <n≦i j (1) This is on the assumption that only the relay controllers 30 are tree-connected, and the uppermost relay controller 30 of the relay unit 20 is connected to one of the lower communication ports 13, etc. of the main controller 10. In this case, the main controller 10 can also be configured to have one lower communication port 13. In this case, for example, one relay controller 30 connected to the lower communication port 13 generates the sum of state quantities, and sends it to the main controller 10 from the upper communication port 31 of the relay controller 30.

[0091] By appropriately determining n and i that satisfy the formula (1) according to the actual arrangement of the power conversion unit 4 and the sub-controller 40, the number of stages of the tree-connected relay controllers 30 can be optimized, and the communication time can be shortened to an optimal length. Also, since the configuration is such that only the relay controller 30 compresses the information of the state quantity, the processing of the main controller 10 can be simplified.

[0092] [Main controller configuration] 11B is a diagram showing a configuration example of a main controller of the third embodiment. The figure is a block diagram showing a configuration example of a main controller 10. The main controller 10 of the third embodiment differs from the relay controller 30 of FIG. 3 in that it has three or more downstream communication ports 13, etc. The main controller 10 of the figure has four downstream communication ports, 13, 14, 15, and 16, like the relay controller 30 of FIG. 11A. These downstream communication ports 13, etc. are connected to the relay controller 30 via a communication path 52.

[0093] As described above, when generating a control command, the main controller 10 in the figure adds the state quantity information received by the lower communication ports 13, 14, 15, and 16. This corresponds to the main controller 10 performing the final information compression of the state quantity information. In this case, it can be considered that the main controller 10 and the multiple relay controllers 30 are tree-connected. Even in this case, n and i that satisfy the formula (1) can be appropriately determined. For example, in FIG. 1, j can be set to 3 (3 stages) by setting i and n to 2 and 8, respectively. Compared with the case where information compression is performed only by the relay controller 30, the number of stages of the tree-connected relay controllers 30 can be reduced.

[0094] In this way, by appropriately selecting the number of lower communication ports of the relay controller 30 or the relay controller 30 and the main controller 10 and the number n of groups of the sub-controllers 40, the communication time of the state quantities can be optimized.

[0095] Although the power conversion device 1 has a configuration in which the outputs of the multiple power conversion units 4 are connected in parallel, the present invention is not limited to this example. For example, the power conversion device 1 may have a configuration in which the outputs of the multiple power conversion units 4 are connected in series. In this case, the sub-controller 40 detects the voltage values ​​output by the power conversion units 4 as state quantities, and the relay controller 30 generates and transmits state quantity information that is a partial sum of these voltage values. The main controller 10 generates an output voltage command for the power conversion device 1, which is a control command, based on the difference between the target value of the output voltage of the power conversion device 1, which is the control target, and the sum of the output voltages of the power conversion units 4.

[0096] Although the power conversion device 1 is a control device that drives a motor, the present invention is not limited to this example. For example, the power conversion device 1 may be various types of power supply devices that supply power to loads other than the motor 2. Furthermore, the power conversion device 1 may be a power conditioner that exchanges power between a power generation device that uses natural energy, such as a solar power generation device or a wind power generation device, and a power grid.

[0097] It should be noted that the effects described in this specification are merely examples and are not limiting, and other effects may also be obtained. [Explanation of symbols]

[0098] 1 Power conversion device 2 Motors 3 Sensor section 4 Power conversion section 10. Main Controller 11, 31, 41 Upper communication port 12, 32, 42 Control section 13, 14, 33, 34, 45 Lower communication ports 20 Relay Section 30, 30a, 30b, 30c, 30d, 30e, 30f Relay controller 40, 40a, 40b, 40c, 40d, 40e, 40f, 40g, 40h, 40i, 40j, 40k, 40l, 40m, 40n Sub-controller 43 Drive unit 44 Current detection section 51, 52, 52a, 52b, 53a, 53b, 54a, 54b, 55a, 55b, 55c, 55d Communication path 56a, 56b bus

Claims

1. a main controller that generates and outputs a control command that is a target value for controlling power conversion performed by a plurality of power conversion units based on state quantity information regarding state quantities of the plurality of power conversion units that supply power to a load; a plurality of sub-controllers each disposed for each of the power conversion units, each sub-controller controlling the power conversion unit based on the control command and acquiring and outputting the state quantity; a relay unit that compresses the state quantities output by the plurality of sub-controllers to generate the state quantity information and transmits the state quantity information to the main controller; Equipped with The relay unit has a plurality of relay controllers, The relay controllers are connected in a tree structure in a plurality of stages. A power conversion device comprising:

2. The main controller generating the control command based on a sum of state quantities of the plurality of power conversion units; The state quantity information is The sum of state quantities output by two or more of the sub-controllers The power conversion device according to claim 1 .

3. The acquisition of the state quantity in the sub-controller includes converting the state quantity detected as an analog quantity into a digital quantity and acquiring the same. The power conversion device according to claim 1 .

4. The relay controller includes: The main controller is connected to a host communication path, which is a communication path connected to the main controller side, and the sub-controller is connected to a plurality of lower communication ports, which are lower communication paths, which are communication paths connected to the sub-controller side. The power conversion device according to claim 1 .

5. The plurality of sub-controllers include Connected in series with the relay controller The power conversion device according to claim 4 .

6. The plurality of relay controllers include j stages are tree-connected, each having one upper communication port and i lower communication ports; The plurality of sub-controllers include They are grouped into n groups, The number n of the groups is i ｊ－１ <n≦i ｊ To fulfill The power conversion device according to claim 5 .

7. The main controller The i number of lower communication ports are provided and the jth stage is tree-connected together with the plurality of relay controllers. The power conversion device according to claim 6 .

8. The relay unit includes: The main controller and the sub-controller are connected for serial communication. The power conversion device according to claim 1 .

9. The main controller Generate and output a single control command The power conversion device according to claim 1 .

10. The plurality of sub-controllers include It also outputs its own status information, The relay unit includes: and transmitting a status obtained by aggregating the statuses output by the plurality of sub-controllers to the main controller. The power conversion device according to claim 1 .

11. generating and outputting a control command that is a target value for controlling power conversion performed by a plurality of power conversion units using state quantity information regarding state quantities of the plurality of power conversion units that supply power to a load; Controlling the power conversion units based on the control command for each of the power conversion units and acquiring and outputting the state quantity; compressing the output state quantities to generate state quantity information, and using the state quantity information to generate the control command; Includes The generation of the state quantity information is performed in a plurality of steps including a step of compressing a plurality of the state quantities to generate the state quantity information, and a step of compressing the generated plurality of the state quantity information to generate new state quantity information. A method for controlling a power conversion device comprising the steps of:

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