# US 10,865,777 B2 · Wind turbine power generation system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,865,777 B2 - Document ID: US10865777B2 - Status: Granted - Kind: B2 - Application number: 15/571,322 - Filed: 2016-05-03 - Published: 2018-05-03 - Granted: 2020-12-15 - Earliest claimed: 2015-05-06 - Assignees: Vestas Wind Systems A/S - Applicants: Vestas Wind Systems A/S - Inventors: Philip Carne Kjær - Web page: https://patentgrep.com/patent/US10865777B2 ## CPC - H02J 3/46: Controlling the sharing of generated power between the generators, sources or networks - F03D 9/25: the apparatus being an electrical generator (F03D9/22 takes precedence) - F03D 9/255: {connected to electrical distribution networks; Arrangements therefor} - H02J 3/381: {Dispersed generators} - H02M 5/42: by static converters - H02M 5/4585: {having a rectifier with controlled elements} - H02J 3/38: Arrangements for feeding a single network from two or more generators or sources in parallel; Arrangements for feeding already energised networks from additional generators or sources in parallel - H02J 2101/28: Wind energy - Y02E 10/72: Wind turbines with rotation axis in wind direction - Y02E 10/76: Power conversion electric or electronic aspects - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - F03D: WIND MOTORS - 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) - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A wind turbine power generation system comprising a rotor shaft coupled to an electrical generator which generates a power output at a first AC voltage level; a converter system that converts the power output of the generator at the first AC voltage level to a converter power output at a second AC voltage level; a transformer that converts the converter system power output at the second AC voltage level to a generation system power output at a third AC voltage level; wherein the converter system comprises a machine-side converter, a line-side converter and a DC-link. The machine-side converter is a line-commutated rectifier, and the transformer is an online tap changer transformer. In another aspect, the invention resides in a wind power plant comprising at least one wind power generation system electrically coupled to a substation for onward transmission to a grid. The substation includes a point of common connection to which the one or more power generation systems electrically connected, and a transformer, wherein the transformer is an online tap changer transformer. ## Claims ### Claim 1 A wind turbine comprising: a rotor shaft coupled to an electrical generator that generates a power output at a first AC voltage level; a converter system that converts the power output of the electrical generator at the first AC voltage level to a converter power output at a second AC voltage level, wherein the converter system comprises a machine-side converter, a line-side converter, and a DC-link coupling the machine-side converter and the line-side converter, and wherein the machine-side converter is a line-commutated rectifier; and an online tap changer transformer that converts the converter power output at the second AC voltage level to a wind turbine power output at a third AC voltage level of an electrical grid connected to the wind turbine, wherein the online tap changer transformer is controlled in dependence on at least one of: a measured speed of the electrical generator, and a measured wind speed. ### Claim 2 (depends on 1) The wind turbine of claim 1, wherein the line-commutated rectifier has a six-pulse bridge configuration. ### Claim 3 (depends on 1) The wind turbine of claim 1, wherein the line-commutated rectifier is phase-controlled. ### Claim 4 (depends on 1) The wind turbine of claim 1, wherein the line-side converter is a force-commutated converter. ### Claim 5 (depends on 4) The wind turbine of claim 4, wherein the force-commutated converter is a three-phase converter. ### Claim 6 (depends on 1) The wind turbine of claim 1, wherein the online tap changer transformer is configured to control a voltage on the DC-link to not exceed a peak value of the first AC voltage level. ### Claim 7 (depends on 1) The wind turbine of claim 1, wherein the electrical generator is a permanent-magnet generator. ### Claim 8 (depends on 1) The wind turbine of claim 1, wherein the electrical generator is a wound-field synchronous generator. ### Claim 9 (depends on 1) The wind turbine of claim 1, wherein the line-commutated rectifier comprises at least one thyristor. ### Claim 10 (depends on 1) The wind turbine of claim 1, wherein the converter system is a full-scale converter system. ### Claim 11 (depends on 1) The wind turbine of claim 1, wherein the online tap changer transformer is controlled further in dependence on a grid voltage level. ### Claim 12 (depends on 1) The wind turbine of claim 1, wherein the wind turbine is included in a wind park with one or more other wind turbine, and wherein the electrical grid comprises an internal grid of the wind park. ### Claim 13 (depends on 1) The wind turbine of claim 1, wherein the electrical grid comprises a mains distribution grid. ### Claim 14 A wind power plant comprising: a plurality of wind turbines connected with an internal grid, wherein the plurality of wind turbines comprises a first wind turbine comprising: a rotor shaft coupled to an electrical generator that generates a power output at a first AC voltage level; a converter system that converts the power output of the electrical generator at the first AC voltage level to a converter power output at a second AC voltage level, wherein the converter system comprises a machine-side converter, a line-side converter, and a DC-link coupling the machine-side converter and the line-side converter, and wherein the machine-side converter is a line-commutated rectifier; and an online tap changer transformer that converts the converter power output at the second AC voltage level to a wind turbine power output at a third AC voltage level of the internal grid, wherein the online tap changer transformer is controlled in dependence on at least one of: a measured speed of the electrical generator, and a measured wind speed.