# US 12,191,779 B2 · AC/DC converter stage for converter system with input series structure with improved common mode performance > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,191,779 B2 - Document ID: US12191779B2 - Status: Granted - Kind: B2 - Application number: 17/946,230 - Filed: 2022-09-16 - Published: 2023-01-12 - Granted: 2025-01-07 - Earliest claimed: 2020-03-17 - Assignees: Huawei Digital Power Technologies Co., Ltd. - Applicants: Huawei Digital Power Technologies Co., Ltd. - Inventors: Piniwan Thiwanka Bandara Wijekoon - Web page: https://patentgrep.com/patent/US12191779B2 ## CPC - H02M 1/44: Circuits or arrangements for compensating for electromagnetic interference in converters or inverters - H02M 7/25: arranged for operation in series, e.g. for multiplication of voltage - H02M 1/0074: {Plural converter units whose inputs are connected in series} - H02M 1/123: {Suppression of common mode voltage or current} - H02M 1/0012: {Control circuits using digital or numerical techniques (in DC/DC converters H02M3/157, H02M3/33515; in DC-AC converters H02M7/53873)} - H02M 3/335: using semiconductor devices only - H02M 7/21: using devices of a triode or transistor type requiring continuous application of a control signal - H02M 7/217: using semiconductor devices only - H02M 7/219: in a bridge configuration - H02M 7/487: Neutral point clamped inverters - 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 An AC/DC converter stage for a converter system with an input series structure. The AC/DC converter stage includes two input terminals for inputting an AC input voltage and at least a first circuit branch with at least two switches that are electrically connected in series at a first connection point, where a first input terminal of the two input terminals is electrically connected to the first connection point of the first circuit branch. At least one first electrical storage provides a DC output voltage and is electrically connected in parallel to the first circuit branch. At least one controllable bidirectional switch is electrically connected between the two input terminals. ## Claims ### Claim 1 An AC/DC converter stage for a converter system with an input series structure, comprising: two input terminals configured to input an AC input voltage through at least one phase unit; at least a first circuit branch with at least two switches that are electrically connected in series at a first connection point, wherein a first input terminal of the two input terminals is electrically connected to the first connection point of the first circuit branch; at least one first electrical storage is configured to provide a DC output voltage and electrically connected in parallel to the first circuit branch; and at least one controllable bidirectional switch is electrically connected between the two input terminals. ### Claim 2 (depends on 1) The AC/DC converter stage according to claim 1, wherein the at least one controllable bidirectional switch is further configured to cause a zero state of the AC/DC converter stage by providing in its conducting state a low impedance current path between the two input terminals. ### Claim 3 (depends on 1) The AC/DC converter stage according to claim 1, wherein the AC/DC converter stage is a bipolar boost converter comprising a second electrical storage and one of the two input terminals is electrically connected via the second electrical storage to the at least one controllable bidirectional switch. ### Claim 4 (depends on 3) The AC/DC converter stage according to claim 3, wherein the at least one controllable bidirectional switch is further configured to cause the zero state of the AC/DC converter stage by providing in its conducting state a current path between the two input terminals via the second electrical storage. ### Claim 5 (depends on 3) The AC/DC converter stage according to claim 3, wherein the first input terminal of the two input terminals is electrically connected via the second electrical storage to the first connection point of the first circuit branch. ### Claim 6 (depends on 1) The AC/DC converter stage according to claim 1, further comprising: a second circuit branch with at least two switches that are electrically connected in series at a second connection point, wherein the second circuit branch is electrically connected in parallel to the first circuit branch and the first electrical storage, wherein the second input terminal of the two input terminals is electrically connected to the second connection point of the second circuit branch. ### Claim 7 (depends on 1) The AC/DC converter stage according to claim 1, wherein the first electrical storage further comprises: at least two first electrical storage elements electrically connected in series at a third connection point. ### Claim 8 (depends on 7) The AC/DC converter stage according to claim 7, wherein, when the AC/DC converter stage comprises only the first circuit branch, the second input terminal of the two input terminals is electrically connected to the third connection point. ### Claim 9 (depends on 7) The AC/DC converter stage according to claim 7, wherein, when the AC/DC converter stage comprises the first circuit branch and the second circuit branch, the third connection point is electrically connected to at least one connection point between two switches of the first circuit branch different to the first connection point via a first switch, and, when the first circuit branch comprises four switches electrically connected in series, the third connection point is electrically connected to at least one connection point between two switches of the second circuit branch different to the second connection point via a second switch, when the second circuit branch comprises four switches electrically connected in series. ### Claim 10 (depends on 1) The AC/DC converter stage according to claim 1, wherein the switches further comprise at least one of: at least one diode, at least one controllable semiconductor switch, and at least one Insulated Gate Bipolar transistor (IGBT). ### Claim 11 (depends on 1) The AC/DC converter stage according to claim 1, wherein the at least one controllable bidirectional switch comprises at least two IGBTs. ### Claim 12 (depends on 1) The AC/DC converter stage according to claim 1, further comprising: two controllable bidirectional switches electrically connected in series at a fourth connection point and configured to provide, in their conducting states, a current path between the two input terminals. ### Claim 13 (depends on 12) The AC/DC converter stage according to claim 12, wherein, when the AC/DC converter stage comprises the first circuit branch and the second circuit branch and the first electrical storage comprises the at least two first electrical storage elements electrically connected in series at the third connection point, the third connection point and the fourth connection point are electrically connected with each other. ### Claim 14 (depends on 12) The AC/DC converter stage according to claim 12, wherein, when the AC/DC converter stage comprises only the first circuit branch, each switch of the first circuit branch further comprises: two diodes electrically connected in series at a fifth connection point, or two IGBTs electrically connected in series at the fifth connection point, or when the AC/DC converter stage comprises the first circuit branch and the second circuit branch, each switch of the first circuit branch and the second circuit branch further comprises: two uncontrollable unidirectional semiconductor switches electrically connected in series at the fifth connection point, or two IGBTs, electrically connected in series at the fifth connection point. ### Claim 15 (depends on 14) The AC/DC converter stage according to claim 14, wherein, when the first electrical storage comprises the at least two first electrical storage elements electrically connected in series at the third connection point, each switch further comprises: one slow recovery diode and one fast recovery diode electrically connected in series at the fifth connection point, wherein, for each switch, a low current diode configured to provide a recovery charge is electrically connected between the fifth connection point and the third connection point; or each switch further comprises: two controllable semiconductor switches electrically connected in series at the fifth connection point, wherein, for each switch, a low current diode configured to ensure an equal voltage drop at the two controllable semiconductor switches is electrically connected between the fifth connection point and the third connection point. ### Claim 16 A converter system with an input series structure comprising: at least one phase unit configured to receive an input AC voltage comprising at least two converter units that are electrically connected in series at the input of the converter system, wherein at least one converter unit of the at least two converter units comprises an AC/DC converter stage as a first converter stage, and the AC/DC-converter stage comprises: two input terminals configured to input an AC input voltage (Vin) to the AC/DC converter stage; at least a first circuit branch with at least two switches that are electrically connected in series at a first connection point, wherein a first input terminal of the two input terminals is electrically connected to the first connection point of the first circuit branch; at least one first electrical storage configured to provide a DC output voltage, the first electrical storage being electrically connected in parallel to the first circuit branch; and at least one controllable bidirectional switch electrically connected between the two input terminals. ### Claim 17 (depends on 16) The converter system according to claim 16, wherein each converter unit of the at least two converter units comprises the AC/DC converter stage as a first converter stage. ### Claim 18 (depends on 16) The converter system according to claim 16, wherein at least one converter unit of the at least two converter units comprises a galvanically isolated DC/DC converter stage as a second converter stage, and the corresponding AC/DC converter stage is configured to supply the isolated DC/DC converter stage with a DC input voltage. ### Claim 19 (depends on 16) The converter system according to claim 16, wherein at least one converter unit of the at least two converter units is packaged in an enclosure. ### Claim 20 (depends on 16) The converter system according to claim 16, wherein each phase unit of the at least one phase unit further comprises the at least two converter units that are electrically connected in series at the input of the converter system.