# US 2021/0281164 A1 · Method for operating power factor correction circuit and method for operating uninterruptible power supply apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0281164 A1 - Document ID: US20210281164A1 - Status: Published application - Kind: A1 - Application number: 17/131,789 - Filed: 2020-12-23 - Published: 2021-09-09 - Earliest claimed: 2020-03-03 - Assignees: Delta Electronics, Inc. - Applicants: Delta Electronics, Inc. - Inventors: Yuan-Fang LAI; Hung-Chieh LIN; Chao-Li KAO; Chao-Lung KUO; Hsin-Chih CHEN; Yi-Ping HSIEH - Web page: https://patentgrep.com/patent/US20210281164A1 ## CPC - H02J 9/062: {for AC powered loads} - H02J 9/063: {Common neutral, e.g. AC input neutral line connected to AC output neutral line and DC middle point} - H02J 7/865: {Battery or charger load switching, e.g. concurrent charging and load supply (H02J7/50 takes precedence)} - H02J 9/061: {for DC powered loads} - H02M 1/4233: {using a bridge converter comprising active switches} - H02M 7/219: in a bridge configuration - H02M 7/44: by static converters - H02M 1/007: {Plural converter units in cascade (push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826)} - Y02B 70/10: Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes - Y02P 80/10: Efficient use of energy, e.g. using compressed air or pressurized fluid as energy carrier - 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) - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS ## Abstract A method for operating a power factor correction (PFC) circuit of an uninterruptible power supply (UPS) apparatus is provided. The PFC circuit includes two T-type converters, and each of the T-type converters includes four switching tubes. The method includes: converting AC input voltage into a positive bus voltage across a first capacitor and a negative bus voltage across a second capacitor that is connected in series with the first capacitor when the UPS apparatus is operated under a normal supply mode; and controlling conduction states of the switching tubes of the T-type converters to balance the positive bus voltage and the negative bus voltage when the UPS apparatus is operated under a battery supply mode. ## Claims ### Claim 1 A method for operating a power factor correction (PFC) circuit of an uninterruptible power supply (UPS) apparatus, wherein the PFC circuit includes two T-type converters, and each of the T-type converters includes four switching tubes, wherein the method comprises: converting AC input voltage into a positive bus voltage across a first capacitor and a negative bus voltage across a second capacitor that is connected in series with the first capacitor when the UPS apparatus is operated under a normal supply mode; and controlling conduction states of the switching tubes of the T-type converters to balance the positive bus voltage and the negative bus voltage when the UPS apparatus is operated under a battery supply mode. ### Claim 2 (depends on 1) The method according to claim 1, wherein a first T-type converter of the T-type converters includes a first switching tube and a second switching tube which are connected in series, and a series connection of the first switching tube and the second switching tube is connected in parallel with a series connection of the first capacitor and the second capacitor, wherein the first T-type converter further includes a third switching tube and a fourth switching tube which are connected in series between a first inductor and a midpoint between the first capacitor and the second capacitor, wherein the method further comprises: controlling the first switching tube and the second switching tube to be turned off and controlling the third switching tube and the fourth switching tube to be turned on when the UPS apparatus is operated under the battery supply mode. ### Claim 3 (depends on 2) The method according to claim 2, wherein a duration during the UPS apparatus operated under the battery supply mode includes a first duration and a second duration, wherein the method further comprises: adjusting the first duration and the second duration to balance the positive bus voltage and the negative bus voltage when the UPS apparatus is operated under the battery supply mode. ### Claim 4 (depends on 3) The method according to claim 3, wherein a second T-type converter of the T-type converters includes a fifth switching tube and a sixth switching tube which are connected in series, and a series connection of the fifth switching tube and the sixth switching tube is connected in parallel with the series connection of the first capacitor and the second capacitor, wherein the second T-type converter further includes a seventh switching tube and an eighth switching tube which are connected in series between the midpoint and a second inductor, wherein the method further comprises: controlling the fifth switching tube to be turned on and controlling the sixth switching tube and the seventh switching tube to be turned off during the first duration when the UPS apparatus is operated under the battery supply mode. ### Claim 5 (depends on 4) The method according to claim 4, wherein the method further comprises: controlling the fifth switching tube and the eight switching tube to be turned off and controlling the sixth switching tube to be turned on during the second duration when the UPS apparatus is operated under the battery supply mode. ### Claim 6 (depends on 3) The method according to claim 3, wherein the method further comprises: increasing the first duration when the positive bus voltage is larger than the negative bus voltage. ### Claim 7 (depends on 3) The method according to claim 3, wherein the method further comprises: increasing the second duration when the positive bus voltage is less than the negative bus voltage. ### Claim 8 A method for operating an uninterruptible power supply (UPS) apparatus, wherein the UPS apparatus includes a PFC circuit, a DC-DC converting circuit, and an inverter circuit coupled to the PFC circuit and the DC-DC converting circuit, wherein the PFC circuit includes two T-type converters, and each of the T-type converters includes four switching tubes, wherein the method comprises: converting, by the PFC circuit, AC input voltage into a positive bus voltage across a first capacitor and a negative bus voltage across a second capacitor that is connected in series with the first capacitor and converting, by the inverter circuit, the positive bus voltage and the negative bus voltage into AC output voltage when the UPS apparatus is operated under a normal supply mode; converting, by the DC-DC converting circuit, DC input voltage into the positive bus voltage and the negative bus voltage and converting, by the inverter circuit, the positive bus voltage and the negative bus voltage into the AC output voltage when the UPS apparatus is operated under a battery supply mode; and controlling conduction states of the switching tubes of the T-type converters to balance the positive bus voltage and the negative bus voltage when the UPS apparatus is operated under the battery supply mode. ### Claim 9 (depends on 8) The method according to claim 8, wherein a first T-type converter of the T-type converters includes a first switching tube and a second switching tube which are connected in series, and a series connection of the first switching tube and the second switching tube is connected in parallel with a series connection of the first capacitor and the second capacitor, wherein the first T-type converter further includes a third switching tube and a fourth switching tube which are connected in series between a first inductor and a midpoint between the first capacitor and the second capacitor, wherein the method further comprises: controlling the first switching tube and the second switching tube to be turned off and controlling the third switching tube and the fourth switching tube to be turned on when the UPS apparatus is operated under the battery supply mode. ### Claim 10 (depends on 9) The method according to claim 9, wherein a duration during the UPS apparatus operated under the battery supply mode includes a first duration and a second duration, wherein the method further comprises: adjusting the first duration and the second duration to balance the positive bus voltage and the negative bus voltage when the UPS apparatus is operated under the battery supply mode. ### Claim 11 (depends on 10) The method according to claim 10, wherein a second T-type converter of the T-type converters includes a fifth switching tube and a sixth switching tube which are connected in series, and a series connection of the fifth switching tube and the sixth switching tube is connected in parallel with the series connection of the first capacitor and the second capacitor, wherein the second T-type converter further includes a seventh switching tube and an eighth switching tube which are connected in series between the midpoint and a second inductor, wherein the method further comprises: controlling the fifth switching tube to be turned on and controlling the sixth switching tube and the seventh switching tube to be turned off during the first duration when the UPS apparatus is operated under the battery supply mode. ### Claim 12 (depends on 11) The method according to claim 11, wherein the method further comprises: controlling the fifth switching tube and the eight switching tube to be turned off and controlling the sixth switching tube to be turned on during the second duration when the UPS apparatus is operated under the battery supply mode. ### Claim 13 (depends on 10) The method according to claim 10, wherein the method further comprises: increasing the first duration when the positive bus voltage is larger than the negative bus voltage. ### Claim 14 (depends on 10) The method according to claim 10, wherein the method further comprises: increasing the second duration when the positive bus voltage is less than the negative bus voltage. ### Claim 15 (depends on 10) The method according to claim 10, wherein the PFC circuit further includes a relay coupled between a commercial AC power supply for supplying the AC input voltage and the first and second inductors, wherein the method further comprises: turning off the relay when the UPS apparatus is operated under the battery supply mode. ### Claim 16 (depends on 15) The method according to claim 15, wherein the UPS apparatus further includes a balance circuit coupled to the PFC circuit, the DC-DC converting circuit and the inverter circuit, wherein the method further comprises: balancing the positive bus voltage and the negative bus voltage via the balance circuit during a transition time for turning off the relay.