# US 2018/0026549 A1 · Method and device for controlling operation of inverter > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0026549 A1 - Document ID: US20180026549A1 - Status: Published application - Kind: A1 - Application number: 15/581,723 - Filed: 2017-04-28 - Published: 2018-01-25 - Earliest claimed: 2016-07-25 - Assignees: Sungrow Power Supply Co., Ltd. - Applicants: Sungrow Power Supply Co., Ltd. - Inventors: Jun XU; Jinhu CAO; Peng CHEN; Peng WANG - Web page: https://patentgrep.com/patent/US20180026549A1 ## CPC - H02M 7/487: Neutral point clamped inverters - H02M 7/537: using semiconductor devices only, e.g. single switched pulse inverters - H02J 3/381: {Dispersed generators} - H02J 2101/25: {involving maximum power point tracking control for photovoltaic sources} - Y02E 10/56: Power conversion systems, e.g. maximum power point trackers - 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) - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract Provided are a method and a device for controlling an operation of an inverter. The method includes: determining whether a direct current side voltage of the inverter is greater than an operation voltage setting threshold; and if no, controlling the inverter to operate according to a five level control strategy; and if yes: adjusting the direct current side voltage by using a maximum power tracking algorithm; adjusting linearly a floating capacitor voltage of the inverter based on the adjusted direct current side voltage; determining whether the adjusted floating capacitor voltage is in a preset range; and if yes, controlling the inverter to operate according to a five level control strategy; and if no, controlling the inverter to operate according to a seven level control strategy. ## Claims ### Claim 1 A method for controlling an operation of an inverter, comprising: determining whether a direct current side voltage of the inverter is greater than an operation voltage setting threshold; and in a case that the direct current side voltage of the inverter is not greater than the operation voltage setting threshold, controlling the inverter to operate according to a five level control strategy; and in a case that the direct current side voltage of the inverter is greater than the operation voltage setting threshold: adjusting the direct current side voltage by using a maximum power tracking algorithm; adjusting linearly a floating capacitor voltage of the inverter based on the adjusted direct current side voltage; determining whether the adjusted floating capacitor voltage is in a preset range, wherein the preset range ranges from a quarter of the operation voltage setting threshold minus a preset threshold to a quarter of the operation voltage setting threshold plus the preset threshold; and controlling the inverter to operate according to a five level control strategy in a case that the adjusted floating capacitor voltage is in the preset range; and controlling the inverter to operate according to a seven level control strategy in a case that the adjusted floating capacitor voltage is not in the preset range. ### Claim 2 (depends on 1) The method according to claim 1, wherein after controlling the inverter to operate according to the five level control strategy, the method further comprises: determining whether the direct current side voltage is greater than a first preset voltage, wherein the first preset voltage is greater than the operation voltage setting threshold; and executing a step of adjusting the direct current side voltage by using the maximum power tracking algorithm in a case that the direct current side voltage is greater than the first preset voltage; and controlling the inverter to operate according to the five level control strategy in a case that the direct current side voltage is not greater than the first preset voltage. ### Claim 3 (depends on 1) The method according to claim 1, wherein the adjusting linearly the floating capacitor voltage of the inverter based on the adjusted direct current side voltage comprises: substituting the adjusted direct current side voltage into a preset linear relation formula to obtain a to-be-used floating capacitor voltage; and adjusting the floating capacitor voltage to the to-be-used floating capacitor voltage. ### Claim 4 (depends on 2) The method according to claim 2, wherein the adjusting linearly the floating capacitor voltage of the inverter based on the adjusted direct current side voltage comprises: substituting the adjusted direct current side voltage into a preset linear relation formula to obtain a to-be-used floating capacitor voltage; and adjusting the floating capacitor voltage to the to-be-used floating capacitor voltage. ### Claim 5 (depends on 3) The method according to claim 3, wherein the preset linear relation formula is Y = U d   c   1 * U fc   2 - U fc   1 * U d   c   2 U d   c   1 - U d   c   2 + U fc   1 - U fc   2 U d   c   1 - U d   c   2  X , wherein Udc1 is a direct current side open-circuit voltage of the inverter, Ufc1 is a floating capacitor voltage corresponding to the direct current side open-circuit voltage of the inverter, Udc2 is the operation voltage setting threshold, Ufc2 a floating capacitor voltage corresponding to the operation voltage setting threshold, X is the direct current side voltage of the inverter and Y is the floating capacitor voltage of the inverter. ### Claim 6 A device for controlling an operation of an inverter, comprising: a first determining unit, configured to determine whether a direct current side voltage of the inverter is greater than an operation voltage setting threshold, wherein a first controlling unit is executed in a case that the direct current side voltage of the inverter is not greater than the operation voltage setting threshold, and a first adjusting unit is executed in a case that the direct current side voltage of the inverter is greater than the operation voltage setting threshold; the first controlling unit, configured to control the inverter to operate according to a five level control strategy; the first adjusting unit, configured to adjust the direct current side voltage by using a maximum power tracking algorithm; a second adjusting unit, configured to adjust linearly a floating capacitor voltage of the inverter based on the adjusted direct current side voltage; a second determining unit, configured to determine whether the adjusted floating capacitor voltage is in a preset range, wherein the preset range ranges from a quarter of the operation voltage setting threshold minus a preset threshold to a quarter of the operation voltage setting threshold plus the preset threshold, and wherein the first controlling unit is executed in a case that the adjusted floating capacitor voltage is in the preset range, and a second controlling unit is executed in a case that the adjusted floating capacitor voltage is not in the preset range; and the second controlling unit, configured to control the inverter to operate according to a seven level control strategy. ### Claim 7 (depends on 6) The device according to claim 6, further comprising: a third determining unit, configured to determine whether the direct current side voltage is greater than a first preset voltage, wherein the first preset voltage is greater than the operation voltage setting threshold, and wherein the first adjusting unit is executed in a case that the direct current side voltage is greater than the first preset voltage, and the first controlling unit is executed in a case that the direct current side voltage is not greater than the first preset voltage. ### Claim 8 (depends on 6) The device according to claim 6, wherein the second adjusting unit comprises: a calculating subunit, configured to substitute the adjusted direct current side voltage into a preset linear relation formula to obtain a to-be-used floating capacitor voltage; and an adjusting subunit, configured to adjust the floating capacitor voltage to the to-be-used floating capacitor voltage. ### Claim 9 (depends on 7) The device according to claim 7, wherein the second adjusting unit comprises: a calculating subunit, configured to substitute the adjusted direct current side voltage into a preset linear relation formula to obtain a to-be-used floating capacitor voltage; and an adjusting subunit, configured to adjust the floating capacitor voltage to the to-be-used floating capacitor voltage. ### Claim 10 (depends on 8) The device according to claim 8, wherein the calculating subunit is specifically configured to substitute the adjusted direct current side voltage into Y = U d   c   1 * U fc   2 - U fc   1 * U d   c   2 U d   c   1 - U d   c   2 + U fc   1 - U fc   2 U d   c   1 - U d   c   2  X to obtain a to-be-used floating capacitor voltage, wherein Udc1 is a direct current side open-circuit voltage of the inverter, Ufc1 is a floating capacitor voltage corresponding to the direct current side open-circuit voltage of the inverter, Udc2 is the operation voltage setting threshold, Ufc2 a floating capacitor voltage corresponding to the operation voltage setting threshold, X is the direct current side voltage of the inverter and Y is the floating capacitor voltage of the inverter. ### Claim 11 An inverter comprising a device for controlling an operation of an inverter, wherein the device for controlling an operation of an inverter comprises: a first determining unit, configured to determine whether a direct current side voltage of the inverter is greater than an operation voltage setting threshold, wherein a first controlling unit is executed in a case that the direct current side voltage of the inverter is not greater than the operation voltage setting threshold, and a first adjusting unit is executed in a case that the direct current side voltage of the inverter is greater than the operation voltage setting threshold; the first controlling unit, configured to control the inverter to operate according to a five level control strategy; the first adjusting unit, configured to adjust the direct current side voltage by using a maximum power tracking algorithm; a second adjusting unit, configured to adjust linearly a floating capacitor voltage of the inverter based on the adjusted direct current side voltage; a second determining unit, configured to determine whether the adjusted floating capacitor voltage is in a preset range, wherein the preset range ranges from a quarter of the operation voltage setting threshold minus a preset threshold to a quarter of the operation voltage setting threshold plus the preset threshold, and wherein the first controlling unit is executed in a case that the adjusted floating capacitor voltage is in the preset range, and a second controlling unit is executed in a case that the adjusted floating capacitor voltage is not in the preset range; and the second controlling unit, configured to control the inverter to operate according to a seven level control strategy. ### Claim 12 (depends on 11) The inverter according to claim 11, further comprising: a third determining unit, configured to determine whether the direct current side voltage is greater than a first preset voltage, wherein the first preset voltage is greater than the operation voltage setting threshold, and wherein the first adjusting unit is executed in a case that the direct current side voltage is greater than the first preset voltage, and the first controlling unit is executed in a case that the direct current side voltage is not greater than the first preset voltage. ### Claim 13 (depends on 11) The inverter according to claim 11, wherein the second adjusting unit comprises: a calculating subunit, configured to substitute the adjusted direct current side voltage into a preset linear relation formula to obtain a to-be-used floating capacitor voltage; and an adjusting subunit, configured to adjust the floating capacitor voltage to the to-be-used floating capacitor voltage. ### Claim 14 (depends on 13) The inverter according to claim 13, wherein the calculating subunit is specifically configured to substitute the adjusted direct current side voltage into Y = U d   c   1 * U fc   2 - U fc   1 * U d   c   2 U d   c   1 - U d   c   2 + U fc   1 - U fc   2 U d   c   1 - U d   c   2  X to obtain a to-be-used floating capacitor voltage, wherein Udc1 is a direct current side open-circuit voltage of the inverter, Ufc1 is a floating capacitor voltage corresponding to the direct current side open-circuit voltage of the inverter, Udc2 is the operation voltage setting threshold, Ufc2 a floating capacitor voltage corresponding to the operation voltage setting threshold, X is the direct current side voltage of the inverter and Y is the floating capacitor voltage of the inverter.