Power conversion device

Patent metadata

Field	Value
Publication number	US-10992219-B2
Application number	US-201716613684-A
Country	US
Kind code	B2
Filing date	Jun 27, 2017
Priority date	Jun 27, 2017
Publication date	Apr 27, 2021
Grant date	Apr 27, 2021

Abstract

A power conversion device includes a plurality of cascaded converter cells. In each of the converter cells, each of a plurality of arms forming a bridge circuit is provided with a plurality of semiconductor switching elements in parallel. A drive controller of each of the converter cells is configured to, when none of a plurality of predetermined abnormality modes is detected, control the bridge circuit in accordance with an externally provided command. The drive controller is configured to, when at least one of the plurality of abnormality modes is detected, turn on all semiconductor switching elements provided in at least one of the plurality of arms forming the bridge circuit, to thereby establish a short circuit between first and second input/output nodes.

First claim

The invention claimed is:

1. A power conversion device comprising a plurality of cascaded converter cells,
each of the converter cells including:
a first input/output node;
a second input/output node;
an energy storage device; and
a bridge circuit configured to switch between connection and disconnection between the first and second input/output nodes and the energy storage device, wherein at least one arm of a plurality of arms forming the bridge circuit includes a plurality of semiconductor switching elements connected in parallel,

wherein between the first input/output node and the second input/output node of each of the converter cells, no switch is provided other than the semiconductor switching elements forming the bridge circuit,
each of the converter cells further including:
a power supply circuit configured to generate a drive voltage based on a voltage held by the energy storage device,
a drive controller configured to operate according to the drive voltage;
a battery power supply; and
at least one latch-type switch connected between an output of the battery power supply and gates of all semiconductor switching elements provided in the at least one arm, each of the semiconductor elements provided in the at least one arm being capable of establishing a short circuit between the first input/output node and the second input/output node,

wherein when the at least one latch-type switch is turned on, the gate of each semiconductor switching element provided in the at least one arm receives a voltage for turning on the semiconductor switching element,
wherein the drive controller is configured to:
when none of a plurality of predetermined abnormality modes is detected, control the bridge circuit in accordance with an externally provided command; and
when at least one of the plurality of abnormality modes is detected, turn on the at least one latch-type switch,

wherein the plurality of abnormality modes includes a voltage of the energy storage device being outside a predetermined range.

2. The power conversion device according to claim 1 , wherein the at least one arm of the plurality of arms forming the bridge circuit includes two semiconductor switching elements connected in parallel as the plurality of semiconductor switching elements.

3. The power conversion device according to claim 1 , wherein the plurality of abnormality modes include communication between the drive controller and outside being abnormal.

4. The power conversion device according to claim 1 , wherein
the plurality of abnormality modes include the drive voltage generated by the power supply circuit being outside a set range.

5. The power conversion device according to claim 1 , wherein:
the bridge circuit includes:
a first arm provided between a positive side node of the energy storage device and the first input/output node; and
a second arm provided between a negative side node of the energy storage device and the first input/output node;

the second input/output node is directly connected to the negative side node of the energy storage device; and
the drive controller is configured to, when at least one of the plurality of abnormality modes is detected, control the bridge circuit such that all semiconductor switching elements forming the second arm are turned on by turning on the at least one latch-type switch.

6. The power conversion device according to claim 5 , wherein:
the at least one latch-type switch includes
a first latch-type switch connected between the output of the battery power supply and a gate of each of the plurality of semiconductor switching elements forming the second arm; and

the drive controller is configured to, when at least one of the plurality of abnormality modes is detected, control the brides circuit such that all semiconductor switching elements forming the second arm are turned on by turning on the first latch-type switch.

7. The power conversion device according to claim 1 , wherein;
the bridge circuit includes:
a first arm provided between a positive side node of the energy storage device and the first input/output node;
a second arm provided between a negative side node of the energy storage device and the first input/output node;
a third arm provided between the positive side node of the energy storage device and the second input/output node; and
a fourth arm provided between the negative side node of the energy storage device and the second input/output node; and

the drive controller is configured to, when at least one of the plurality of abnormality modes is detected, control the bridge circuit such that all semiconductor switching elements forming the second arm and the fourth arm are turned on by turning on the at-least one latch-type switch.

8. The power conversion device according to claim 7 , wherein:
the at least one latch-type switch includes:
a first latch-type switch connected between the output of the battery power supply and a gate of each of the plurality of semiconductor switching elements forming the second arm; and
a second latch-type switch connected between the output of the battery power supply and a gate of each of the plurality of semiconductor switching elements forming the fourth arm; and

the drive controller is configured to, when at least one of the plurality of abnormality modes is detected, control the bridge circuit such that all semiconductor switching elements forming the second arm are turned on by turning on the first latch-type switch, and control the bridge circuit such that all semiconductor switching elements forming the fourth arm are turned on by turning on the second latch-type switch.

9. The power conversion device according to claim 1 , wherein:
the bridge circuit includes:
a first arm provided between a positive side node of the energy storage device and the first input/output node;
a second arm provided between a negative side node of the energy storage device and the first input/output node;
a third arm provided between the positive side node of the energy storage device and the second input/output node; and
a fourth arm provided between the negative side node of the energy storage device and the second input/output node; and

the drive controller is configured to, when at least one of the plurality of abnormality modes is detected, control the bridge circuit such that all semiconductor switching elements forming the first arm and the third arm are turned on by turning on the at least one latch-type switch.

10. The power conversion device according to claim 1 , further comprising a central control unit configured to:
transmit a control command and an operation/stop command to each of the converter cells;
acquire information about a number of failed cells which have been short-circuited between the first input/output node and the second input/output node due to detection of any of the plurality of abnormality modes; and
when the number of failed cells exceeds a predetermined threshold value, stop operation of the power conversion device.

11. A reactive power compensation device comprising the power conversion device according to claim 1 .

12. A power conversion device comprising:
a plurality of cascaded converter cells each including:
an energy storage device; and
a bridge circuit wherein at least one arm forming the bridge circuit includes a plurality of semiconductor switching elements connected in parallel;

a power supply circuit configured to generate a drive voltage based on a voltage held by the energy storage device;
a drive controller configured to operate according to the drive voltage;
a battery power supply; and
at least one latch-ty

Assignees

• Mitsubishi Electric Corp

Inventors

• Takahashi Tatsuya
• Hayashi Shigeo

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

• H02M7/483

  Converters with outputs that each can have more than two voltages levels · CPC title

• H02M1/4208

  Arrangements for improving power factor of AC input · CPC title

• H02M7/53871

  with automatic control of output voltage or current · CPC title

• H02M1/32 Primary

  Means for protecting converters other than automatic disconnection · CPC title