# US 11,309,803 B2 · Power converter for trasmitting power between networks > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,309,803 B2 - Document ID: US11309803B2 - Status: Granted - Kind: B2 - Application number: 16/878,732 - Filed: 2020-05-20 - Published: 2020-11-26 - Granted: 2022-04-19 - Earliest claimed: 2019-05-21 - Assignees: Vacon Oy - Applicants: Vacon Oy - Inventors: Stefan Schroeder; Dan Isaksson; Risto Komulainen; Stefan Strandberg - Web page: https://patentgrep.com/patent/US11309803B2 ## CPC - H02M 5/4585: {having a rectifier with controlled elements} - H02M 7/49: Combination of the output voltage waveforms of a plurality of converters - H02M 1/0043: {Converters switched with a phase shift, i.e. interleaved (non-isolated DC/DC converters H02M3/1586)} - H02M 1/0074: {Plural converter units whose inputs are connected in series} - H02M 1/0077: {Plural converter units whose outputs are connected in series} - H02M 3/33584: {Bidirectional converters} - H02M 5/225: {comprising two stages of AC-AC conversion, e.g. having a high frequency intermediate link} - H02M 7/4807: {having a high frequency intermediate AC stage} - 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 converter circuitry between a first network, which may be either a poly-phase medium-voltage alternating current (AC) network, at least one polyphase low-voltage AC network or at least one direct-current (DC) network, and a second network, which may be either a polyphase medium-voltage AC network or a medium-voltage DC network, wherein the converter circuitry comprises at least one power bus and low-voltage power cells both at the first and at the second network side such that each power cell is connected to a power bus via a transformer. Each power bus is connected to a low-voltage power unit, which is able to supply pre-charging power via the power bus to all power cell intermediate DC-link filtering capacitors before the converter is started. The low-voltage power unit is also able to take care of a resistor braking in case the first network cannot take the power supplied by the load connected to the second network. ## Claims ### Claim 1 A converter circuitry configured to transmit power between a first electricity network and a second electricity network, the first electricity network being either a single-phase DC network or a polyphase AC network, and the second electricity network being either a single-phase DC network or a polyphase AC network, the converter circuitry comprising: a plurality of low-voltage power cells which are connected from their input connections (IN) to the first electricity network, a plurality of low-voltage power cells which are connected from their input connections (IN) to the second electricity network, at least one power bus, wherein the output connections (OUT) of each power cell are coupled to a power bus via a transformer, and wherein each low-voltage power cell comprises an intermediate DC link capacitor and a controllable power semiconductor H-bridge coupled to the output connection (OUT), and wherein the at least one power bus is coupled to a low-voltage power unit which is able to generate an AC voltage with varying pulse ratio to all power buses connected to it. ### Claim 2 (depends on 1) The converter circuitry of claim 1, wherein the low-voltage power unit, before the converter circuitry is connected to the first electricity network, is configured to generate a rectangular AC voltage, whose pulse ratio increases from 0 to 50%, to the at least one power bus and thereby charge up the intermediate DC link capacitors of all low-voltage power cells belonging to the converter circuitry. ### Claim 3 (depends on 2) The converter circuitry of claim 2, further comprising a control unit, operatively connected to those H-bridges which are coupled to the output connections (OUT) of the low-voltage power cells, which control unit is configured to control the H-bridge controllable semiconductor switches during converter operation such that the voltage patterns of all the output connections (OUT) of the low-voltage power cells, connected to a same power bus, are essentially cophasal with 50% pulse ratio. ### Claim 4 (depends on 2) The converter circuitry of claim 2 in a system wherein the second electricity network is a medium-voltage level polyphase AC network, and wherein the power cells on the second electricity network side are arranged such that the number of power cells associated with each second electricity network phase is equal and the input connections (IN) of the single or parallel coupled power cells at each phase are connected in series. ### Claim 5 (depends on 2) The converter circuitry of claim 2 in a system wherein the second electricity network is a medium-voltage level DC network, and wherein the power cells on the second electricity network side are arranged such that the input connections (IN) of the single or parallel coupled power cells are connected in series. ### Claim 6 (depends on 1) The converter circuitry of claim 1, further comprising a control unit, operatively connected to those H-bridges which are coupled to the output connections (OUT) of the low-voltage power cells, which control unit is configured to control the H-bridge controllable semiconductor switches during converter operation such that the voltage patterns of all the output connections (OUT) of the low-voltage power cells, connected to a same power bus, are essentially cophasal with 50% pulse ratio. ### Claim 7 (depends on 6) The converter circuitry of claim 6, wherein the number of power buses is at least 2 and wherein, during converter operation, the control unit is configured to control the controllable semiconductor switches of those H-bridges which are coupled to the output connections (OUT) of the low-voltage power cells such that there is a phase shift angle between voltage patterns of the at least 2 power buses. ### Claim 8 (depends on 7) The converter circuitry of claim 7 in a system wherein the second electricity network is a medium-voltage level polyphase AC network, and wherein the power cells on the second electricity network side are arranged such that the number of power cells associated with each second electricity network phase is equal and the input connections (IN) of the single or parallel coupled power cells at each phase are connected in series. ### Claim 9 (depends on 6) The converter circuitry of claim 6, comprising one power bus. ### Claim 10 (depends on 9) The converter circuitry of claim 9 in a system wherein the second electricity network is a medium-voltage level polyphase AC network, and wherein the power cells on the second electricity network side are arranged such that the number of power cells associated with each second electricity network phase is equal and the input connections (IN) of the single or parallel coupled power cells at each phase are connected in series. ### Claim 11 (depends on 6) The converter circuitry of claim 6 in a system wherein the second electricity network is a medium-voltage level polyphase AC network, and wherein the power cells on the second electricity network side are arranged such that the number of power cells associated with each second electricity network phase is equal and the input connections (IN) of the single or parallel coupled power cells at each phase are connected in series. ### Claim 12 (depends on 6) The converter circuitry of claim 6 in a system wherein the second electricity network is a medium-voltage level DC network, and wherein the power cells on the second electricity network side are arranged such that the input connections (IN) of the single or parallel coupled power cells are connected in series. ### Claim 13 (depends on 1) The converter circuitry of claim 1 in a system wherein the second electricity network is a medium-voltage level polyphase AC network, and wherein the power cells on the second electricity network side are arranged such that the number of power cells associated with each second electricity network phase is equal and the input connections (IN) of the single or parallel coupled power cells at each phase are connected in series. ### Claim 14 (depends on 1) The converter circuitry of claim 1 in a system wherein the second electricity network is a medium-voltage level DC network, and wherein the power cells on the second electricity network side are arranged such that the input connections (IN) of the single or parallel coupled power cells are connected in series. ### Claim 15 (depends on 1) The converter circuitry of claim 1 in a system wherein the first electricity network is a medium-voltage level polyphase AC network, and wherein the power cells on the first electricity network side are arranged such that the number of power cells associated with each first electricity network phase is equal and the input connections (IN) of the single or parallel coupled power cells at each phase are connected in series. ### Claim 16 (depends on 1) The converter circuitry of claim 1 in a system, wherein the first electricity network comprises at least one low-voltage level polyphase AC network, and wherein the input connection (IN) of each power cell at the first electricity network side is connected to one low-voltage level polyphase AC network. ### Claim 17 (depends on 1) The converter circuitry of claim 1 in a system, wherein the first electricity network comprises at least one low-voltage level DC network, and wherein the input connection (IN) of each power cell at the first electricity network side are connected to one low-voltage level DC network. ### Claim 18 (depends on 1) The converter circuitry of claim 1 in a system, wherein the first electricity network is a medium-voltage level DC network, and wherein the input connections (IN) of the single or parallel coupled power cells at the first electricity network side are connected in series. ### Claim 19 (depends on 1) A method in a converter circuitry of claim 1 for controlling a H-bridge of a low-voltage power unit, the method comprising an initial phase where the H-bridge generates to the at least one power bus a rectangular AC voltage whose pulse ratio increases from 0 to 50%, and a normal operation phase where the H-bridge operation is stopped. ### Claim 20 (depends on 1) A method in a converter circuitry of claim 1, the method comprising control of the controllable semiconductor switches of those H-bridges, which are coupled to the output connections (OUT) of the low-voltage power cells, during converter operation such that the voltage patterns of all power cell output connections, connected to a same power bus, are essentially cophasal with 50% pulse ratio.