Power conversion device and communication method

Patent metadata

Field	Value
Publication number	US-10819217-B2
Application number	US-201716483529-A
Country	US
Kind code	B2
Filing date	Mar 3, 2017
Priority date	Mar 3, 2017
Publication date	Oct 27, 2020
Grant date	Oct 27, 2020

Abstract

A power conversion device includes: power conversion circuitry including a plurality of submodules connected in series to each other; a protection device generating a protection command for protecting each submodule; and one or more relay devices outputting the protection command to each submodule. The relay device includes: a first communication circuit for communicating with the protection device; and a second communication circuit for communicating with the power conversion circuitry. The first communication circuit transmits the stop command to the second communication circuit through a first communication channel, and transmits different information different from the stop command to the second communication circuit through a second communication channel. The communication speed of communication through the first communication channel is higher than that of communication through the second communication channel.

First claim

The invention claimed is:

1. A power conversion device performing power conversion between a DC circuit and an AC circuit, the power conversion device comprising:
power conversion circuitry including a plurality of submodules connected in series to each other;
a protection device configured to generate a protection command for protecting each of the submodules; and
a plurality of relay devices configured to output the protection command to each of the submodules,
the protection command including a stop command for stopping operation of each of the submodules,
the relay devices each including:
a first communication circuit configured to communicate with the protection device; and
a second communication circuit configured to communicate with the power conversion circuitry,
the first communication circuit being configured to transmit the stop command to the second communication circuit through a first communication channel, and transmit different information different from the stop command to the second communication circuit through a second communication channel,

a communication speed of communication between the first communication circuit and the second communication circuit through the first communication channel being higher than a communication speed of communication between the first communication circuit and the second communication circuit through the second communication channel,
the second communication circuit being configured to transmit a communication frame to each of the submodules at a predetermined period, the communication frame containing the stop command and the different information received from the first communication circuit.

2. The power conversion device according to claim 1 , further comprising a control device configured to generate a control command for controlling operation of each of the submodules, wherein
the control command includes a synchronization command for synchronizing respective operations of the submodules,
the relay devices are configured to output the control command to each of the submodules, and
the first communication circuit is configured to transmit the synchronization command to the second communication circuit through the first communication channel.

3. The power conversion device according to claim 2 , wherein each of the control device and the protection device is connected to the relay devices through a ring-type network.

4. The power conversion device according to claim 3 , wherein
the control device is configured to transmit, to the relay devices,
a first communication frame containing a different command which is included in the control command besides the synchronization command, and
a second communication frame containing the synchronization command which is included in the control command.

5. The power conversion device according to claim 4 , wherein
the power conversion circuitry includes:
a high-potential-side DC terminal and a low-potential-side DC terminal that are connected to the DC circuit; and
a plurality of leg circuits corresponding to respective phases of the AC circuit and connected in parallel with each other between the high-potential-side DC terminal and the low-potential-side DC terminal,

the plurality of leg circuits each include:
a connecting part connected electrically to a corresponding phase of the AC circuit;
an upper arm including multiple submodules among the plurality of submodules, the multiple submodules being connected in series to each other between the connecting part and the high-potential-side DC terminal; and
a lower arm including multiple submodules among the plurality of submodules, the multiple submodules being connected in series to each other between the connecting part and the low-potential-side DC terminal, and

the different command includes an output voltage command value for the upper arm, and an output voltage command value for the lower arm.

6. The power conversion device according to claim 5 , wherein the control device is configured to transmit the first communication frame to the relay devices and thereafter transmit the second communication frame to the relay devices.

7. The power conversion device according to claim 3 , wherein the relay devices are each connected through a star-type network to a predetermined number of submodules among the plurality of submodules.

8. The power conversion device according to claim 2 , wherein the relay devices are each connected through a star-type network to a predetermined number of submodules among the plurality of submodules.

9. The power conversion device according to claim 1 , wherein the relay devices are each connected through a star-type network to a predetermined number of submodules among the plurality of submodules.

10. A power conversion device performing power conversion between a DC circuit and an AC circuit, the power conversion device comprising:
power conversion circuitry including a plurality of submodules connected in series to each other;
a control device configured to generate a control command for controlling operation of each of the submodules;
a protection device configured to generate a protection command for protecting each of the submodules; and
a plurality of relay devices configured to output the protection command and the control command to each of the submodules,
the protection command including a stop command for stopping operation of each of the submodules,
the control command including a synchronization command for synchronizing respective operations of the submodules,
the control device being connected to the plurality of relay devices through a ring-type network,
the relay devices being each connected to a predetermined number of submodules among the plurality of submodules through a star-type network,
the control device being configured to transmit, to the plurality of relay devices,
a first communication frame containing a different command which is included in the control command besides the synchronization command, and
a second communication frame containing the synchronization command which is included in the control command,

the relay devices each being configured to transmit a communication frame to each of the submodules at a predetermined period, the communication frame containing the stop command and the control command.

11. A communication method used for a power conversion device performing power conversion between a DC circuit and an AC circuit,
the power conversion device comprising:
power conversion circuitry including a plurality of submodules connected in series to each other;
a protection device configured to generate a protection command for protecting each of the submodules; and
a plurality of relay devices configured to output the protection command to each of the submodules,
the protection command including a stop command for stopping operation of each of the submodules,
the relay devices each including:
a first communication circuit configured to communicate with the protection device; and
a second communication circuit configured to communicate with the power conversion circuitry,

the communication method comprising:
transmitting, by the first communication circuit, the stop command to the second communication circuit through a first communication channel;
transmitting, by the first communication circuit, different information different from the stop command to the second communication circuit through a second communication channel,
a communication speed of communication between the first communication circuit and the second communication circuit through the first communication channel being higher than a communication speed o

Assignees

• Mitsubishi Electric Corp

Inventors

• Ido Yasunori
• Tokunaga Muneharu
• Ohashi Hideaki

Classifications

• H02M7/4835

  comprising two or more cells, each including a switchable capacitor, the capacitors having a nominal charge voltage which corresponds to a given fraction of the input voltage, and the capacitors being selectively connected in series to determine the instantaneous output voltage · CPC title

• H02M1/36 Primary

  Means for starting or stopping converters · CPC title

• H02M1/32 Primary

  Means for protecting converters other than automatic disconnection · CPC title

• H02M1/0012

  Control circuits using digital or numerical techniques (in DC/DC converters H02M3/157, H02M3/33515; in DC-AC converters H02M7/53873) · CPC title

• H02M7/797

  using semiconductor devices only · CPC title