# US 2023/0275437 A1 · Power distribution device and method using droop control > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2023/0275437 A1 - Document ID: US20230275437A1 - Status: Published application - Kind: A1 - Application number: 18/024,192 - Filed: 2022-05-19 - Published: 2023-08-31 - Earliest claimed: 2021-06-23 - Assignees: LG Energy Solution, Ltd. - Applicants: LG Energy Solution, Ltd. - Inventors: Jongcheol KIM; Hyeungil JO; Inho JUNG - Web page: https://patentgrep.com/patent/US20230275437A1 ## CPC - H02J 3/32: using batteries or super capacitors with converting means - H02J 7/50: acting upon multiple batteries simultaneously or sequentially - H02J 3/12: Arrangements for adjusting voltage in AC networks by changing a characteristic of the network load - H02J 7/933: {the cycle being controlled or terminated in response to electric parameters} - H02J 7/96: in response to battery voltage - H02M 3/158: including plural semiconductor devices as final control devices for a single load - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - 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 distribution apparatus may comprise a converter configured to perform DC-DC conversion between a battery and a power conversion system; and a controller configured to set a droop curve for controlling an output of the converter based on a state of each battery, wherein the converter is configured to receive and store information on the droop curve set by the controller, detect a voltage change in a DC link between the power conversion system and the converter, the voltage change being caused by a start of a charging or a discharging operation, and control the output of the converter based on a detected DC link voltage and the droop curve. ## Claims ### Claim 1 A power distribution apparatus, comprising: a converter configured to perform DC-DC conversion between a battery and a power conversion system (PCS); and a controller configured to set a droop curve for controlling an output of the converter based on a state of the battery, wherein the converter is configured to: receive and store information on the droop curve set by the controller, detect a voltage change in a DC link between the PCS and the converter, the voltage change being caused by a start of a charging or a discharging operation, and control the output of the converter based on a detected DC link voltage and the droop curve. ### Claim 2 (depends on 1) The power distribution apparatus of claim 1, wherein the droop curve indicates a relationship between the voltage of the DC link and an output power of the converter. ### Claim 3 (depends on 1) The power distribution apparatus of claim 1, wherein the converter is further configured to: derive an output power matching the detected DC link voltage in the droop curve, set the derived output power as an output reference of the converter, and control the output of the converter based on the output reference. ### Claim 4 (depends on 1) The power distribution apparatus of claim 1, wherein the droop curve includes a dead band in which neither charging nor discharging is performed for a predetermined range of DC link voltages. ### Claim 5 (depends on 1) The power distribution apparatus of claim 1, wherein the PCS is connected to a plurality of converters including the converter, the plurality of converters being configured to perform DC-DC conversion respectively between the PCS and a plurality of batteries including the battery, and wherein charging or discharging is completed at a DC link voltage at which a sum of outputs of the plurality of converters connected to the PCS matches a power of the PCS, thereby maintaining balance. ### Claim 6 (depends on 1) The power distribution apparatus of claim 1, wherein a slope of the droop curve for the battery is set based on the state of the battery, and the droop curve includes information on a maximum charge power and a maximum discharge power. ### Claim 7 A power distribution method in a converter configured to perform DC-DC conversion between a battery among a plurality of batteries and a power conversion system (PCS), the method comprising: receiving information on a droop curve for controlling an output of the converter from a controller configured to manage states of the plurality of batteries and storing the received information on a droop curve; detecting a voltage change at a DC link between the PCS and the converter; and controlling an output of the converter according to a detected DC link voltage and the droop curve to discharge or charge the battery among the plurality of batteries. ### Claim 8 (depends on 7) The power distribution method of claim 7, wherein the droop curve indicates a relationship between the voltage of the DC link and an output power of the converter. ### Claim 9 (depends on 7) The power distribution method of claim 7, wherein the controlling of the output of the converter includes: setting an output power matching the detected DC link voltage in the droop curve as an output reference of the converter. and controlling the output of the converter based on the output reference. ### Claim 10 (depends on 7) The power distribution method of claim 7, wherein the droop curve includes a dead band in which neither charging nor discharging is performed for a predetermined range of DC link voltages. ### Claim 11 (depends on 7) The power distribution method of claim 7, wherein the PCS is connected to a plurality of converters including the converter, the plurality of converters being configured to perform DC-DC conversion respectively between the PCS and the plurality of batteries, and wherein charging or discharging is completed at a DC link voltage at which a sum of outputs of the plurality of converters connected to the PCS matches a power of the PCS, thereby maintaining balance. ### Claim 12 (depends on 7) The power distribution method of claim 7, wherein a slope of the droop curve for the battery is set based on a state of the battery, and the droop curve includes information on a maximum charge power and a maximum discharge power. ### Claim 13 (depends on 7) The power distribution method of claim 7, wherein the controlling of the output of the converter comprises: calculating an output reference from the droop curve using the detected DC link voltage; controlling the output of the converter based on the output reference; and terminating the charging or discharging if the DC link voltage has reached a balance. ### Claim 14 A converter configured to perform DC-DC conversion between a battery and a power conversion system (PCS), the converter comprising: a memory configured to store information on a droop curve for controlling an output of the converter; and a processor configured to: detect a voltage change at a DC link between the PCS and the converter; and control an output of the converter according to a detected DC link voltage and the stored information on the droop curve. ### Claim 15 (depends on 14) The converter of claim 14, wherein the droop curve indicates a relationship between the voltage of the DC link and an output power of the converter. ### Claim 16 (depends on 14) The converter of claim 14, wherein the processor is further configured to: derive an output power matching the detected DC link voltage in the droop curve; set the derived output power as an output reference of the converter; and control the output of the converter based on the output reference of the converter. ### Claim 17 (depends on 14) The converter of claim 14, wherein the droop curve includes a dead band in which neither charging nor discharging is performed for a predetermined range of DC link voltages. ### Claim 18 (depends on 14) The converter of claim 14, wherein the PCS is connected to a plurality of converters including the converter, the plurality of converters being configured to perform DC-DC conversion respectively between the PCS and the plurality of batteries including the battery, and wherein charging or discharging is completed at a DC link voltage at which a sum of the outputs of the plurality of converters connected to the PCS matches a power of the PCS, thereby maintaining balance. ### Claim 19 (depends on 14) The converter of claim 14, wherein a slope of the droop curve for the battery is set based on a state of the battery, and the droop curve includes information on a maximum charge power and a maximum discharge power. ### Claim 20 An energy storage system comprising: a plurality of battery racks; a plurality of converters each configured to perform DC-DC conversion for a corresponding one of the plurality of battery racks; a power conversion system connected between the plurality of converters and a power grid; and a battery section controller configured to determine droop curves for controlling outputs of the converters according to states of the battery racks, respectively, wherein each converter among the plurality of converters is configured to: receive and store information on a corresponding one of the droop curves determined by the battery section controller, detect a voltage change in a DC link between the power conversion system and the converter, the voltage change being caused by a start of a charging or a discharging operation, and control an output of the converter based on a detected DC link voltage and the corresponding droop curve.