# US 11,909,307 B2 · Power conversion device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,909,307 B2 - Document ID: US11909307B2 - Status: Granted - Kind: B2 - Application number: 17/615,850 - Filed: 2019-06-12 - Published: 2022-09-29 - Granted: 2024-02-20 - Earliest claimed: 2019-06-12 - Assignees: Mitsubishi Electric Corporation - Applicants: Mitsubishi Electric Corporation - Inventors: Kazuyori Tahata; Shuhei Fujiwara; Takuya Kajiyama; Toshiyuki Fujii - Web page: https://patentgrep.com/patent/US11909307B2 ## CPC - H02M 1/325: {with means for allowing continuous operation despite a fault, i.e. fault tolerant converters} - H02M 7/4835: {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} - H02M 1/0043: {Converters switched with a phase shift, i.e. interleaved (non-isolated DC/DC converters H02M3/1586)} - H02M 1/32: Means for protecting converters other than automatic disconnection - H02M 7/217: using semiconductor devices only - H02M 7/5395: by pulse-width modulation - H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P) ## Abstract A power conversion device includes a power converter including a plurality of arms and a control device to control voltages of a plurality of sub modules by PWM control using a carrier signal for each sub module. The sub module includes a plurality of switching elements, a power storage element, a pair of output terminals, and a bypass switch. When the control device detects failure of a sub module in an arm, it performs stop processing for stopping a switching operation of the plurality of switching elements included in at least one sub module of the plurality of sub modules in the arm and has the sub module failure of which was detected bypassed. After the control device performs the stop processing, it equalizes intervals among phases of carrier signals of a plurality of normal sub modules in the arm caused by failure of the sub module. ## Claims ### Claim 1 A power conversion device comprising: a power converter including a plurality of arms, each arm including a plurality of sub modules connected in series; and a control device to control voltages of the plurality of sub modules by PWM control using a carrier signal for each sub module, the sub module including a plurality of switching elements, a power storage element, a pair of output terminals, and a bypass switch to bypass the sub module, wherein when the control device detects failure of one or more sub modules among the sub modules included in the arm, the control device performs stop processing for turning off the sub modules included in the arm and has the sub module failure of which was detected bypassed, and after the control device performs the stop processing, the control device equalizes uneven intervals among phases of carrier signals of a plurality of normal sub modules in the arm caused by failure of the one or more sub modules. ### Claim 2 (depends on 1) The power conversion device according to claim 1, wherein the control device sets a reference phase of a carrier signal for each sub module and generates the carrier signal having the set reference phase, and when the control device detects failure of the one or more sub modules, the control device equalizes intervals among reference phases of the carrier signals of the plurality of normal sub modules in the arm. ### Claim 3 (depends on 1) The power conversion device according to claim 1, wherein when output power from the power converter is equal to or higher than a first threshold value at time of detection of failure of the one or more sub modules in the arm and a predetermined condition is satisfied, the control device performs the stop processing, and when output power from the power converter is lower than the first threshold value at the time of detection of failure of the one or more sub modules in the arm, the control device performs the stop processing regardless of the predetermined condition. ### Claim 4 (depends on 1) The power conversion device according to claim 1, wherein when the control device detects failure of the one or more sub modules in the arm, the control device gradually lowers output power from the power converter, and when output power becomes lower than a second threshold value, the control device performs the stop processing. ### Claim 5 (depends on 1) The power conversion device according to claim 1, wherein the stop processing for turning off the sub modules includes setting the plurality of switching elements included in each of the sub modules to an off state. ### Claim 6 (depends on 1) The power conversion device according to claim 1, wherein the stop processing for turning off the sub modules includes setting the plurality of switching elements included in each of sub modules to an off state, and when the control device detects failure of the sub module in the arm, the control device performs the stop processing at timing when a voltage command value for the arm becomes equal to or larger than a first command value and controls an arm current that flows through the arm to flow in a positive direction, or performs the stop processing at timing when the voltage command value for the arm becomes smaller than a second command value smaller than the first command value and controls the arm current that flows through the arm to flow in a negative direction. ### Claim 7 A power conversion device comprising: a power converter including a plurality of arms, each arm including a plurality of sub modules connected in series, and a control device to control voltages of the plurality of sub modules by PWM control using a carrier signal for each sub module, the sub module including a plurality of switching elements, a power storage element, a pair of output terminals, and a bypass switch to bypass the sub module, wherein the sub modules in the arm are categorized into a plurality of groups, when the control device detects failure of the sub module in the arm, the control device stops the switching operation of the plurality of switching elements included in a sub module belonging to a first group, sets a phase of a carrier signal of a normal sub module belonging to the first group so as to equalize intervals among phases of carrier signals of a plurality of normal sub modules in the arm, and restarts the switching operation after setting the phase of the carrier signal of the normal sub module belonging to the first group, and after the switching operation is restarted, the control device stops the switching operation of the plurality of switching elements included in a sub module belonging to a second group, sets a phase of a carrier signal of a normal sub module belonging to the second group so as to equalize intervals among phases of carrier signals of a plurality of normal sub modules in the arm, and restarts the switching operation after setting the phase of the carrier signal of the normal sub module belonging to the second group. ### Claim 8 (depends on 7) The power conversion device according to claim 7, wherein the stop of the switching operation of the plurality of switching elements included in a sub module belonging to each group of the plurality of groups includes setting the plurality of switching elements to an off state. ### Claim 9 (depends on 7) The power conversion device according to claim 7, wherein the control device stops, for each of the plurality of groups, the switching operation of the plurality of switching elements included in a normal sub module belonging to the group, by fixing the switching element connected in parallel to the bypass switch to an on state among the plurality of switching elements included in the normal sub module belonging to the group and fixing the switching element not connected in parallel to the bypass switch to an off state. ### Claim 10 (depends on 2) The power conversion device according to claim 2, wherein when output power from the power converter is equal to or higher than a first threshold value at time of detection of failure of the one or more sub modules in the arm and a predetermined condition is satisfied, the control device performs the stop processing, and when output power from the power converter is lower than the first threshold value at the time of detection of failure of the one or more sub modules in the arm, the control device performs the stop processing regardless of the predetermined condition. ### Claim 11 (depends on 2) The power conversion device according to claim 2, wherein when the control device detects failure of the one or more sub modules in the arm, the control device gradually lowers output power from the power converter, and when output power becomes lower than a second threshold value, the control device performs the stop processing. ### Claim 12 (depends on 2) The power conversion device according to claim 2, wherein the stop processing for turning off the sub modules includes setting the plurality of switching elements included in each of the sub modules to an off state. ### Claim 13 (depends on 3) The power conversion device according to claim 3, wherein the stop processing for turning off the sub modules includes setting the plurality of switching elements included in each of the sub modules to an off state. ### Claim 14 (depends on 4) The power conversion device according to claim 4, wherein the stop processing for turning off the sub modules includes setting the plurality of switching elements included in each of the sub modules to an off state. ### Claim 15 (depends on 2) The power conversion device according to claim 2, wherein the stop processing for turning off the sub modules includes setting the plurality of switching elements included in each of sub modules to an off state, and when the control device detects failure of the sub module in the arm, the control device performs the stop processing at timing when a voltage command value for the arm becomes equal to or larger than a first command value and controls an arm current that flows through the arm to flow in a positive direction, or performs the stop processing at timing when the voltage command value for the arm becomes smaller than a second command value smaller than the first command value and controls the arm current that flows through the arm to flow in a negative direction. ### Claim 16 (depends on 3) The power conversion device according to claim 3, wherein the stop processing for turning off the sub modules includes setting the plurality of switching elements included in each of sub modules to an off state, and when the control device detects failure of the sub module in the arm, the control device performs the stop processing at timing when a voltage command value for the arm becomes equal to or larger than a first command value and controls an arm current that flows through the arm to flow in a positive direction, or performs the stop processing at timing when the voltage command value for the arm becomes smaller than a second command value smaller than the first command value and controls the arm current that flows through the arm to flow in a negative direction. ### Claim 17 (depends on 4) The power conversion device according to claim 4, wherein the stop processing for turning off the sub modules includes setting the plurality of switching elements included in each of sub modules to an off state, and when the control device detects failure of the sub module in the arm, the control device performs the stop processing at timing when a voltage command value for the arm becomes equal to or larger than a first command value and controls an arm current that flows through the arm to flow in a positive direction, or performs the stop processing at timing when the voltage command value for the arm becomes smaller than a second command value smaller than the first command value and controls the arm current that flows through the arm to flow in a negative direction.