# US 2019/0376489 A1 · System and Method for Minimizing Inrush of Current During Start-Up of an Electrical Power System > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0376489 A1 - Document ID: US20190376489A1 - Status: Published application - Kind: A1 - Application number: 16/001,489 - Filed: 2018-06-06 - Published: 2019-12-12 - Earliest claimed: 2018-06-06 - Assignees: General Electric Company - Applicants: General Electric Company - Inventors: Cornelius Edward Holliday; David Smith - Web page: https://patentgrep.com/patent/US20190376489A1 ## CPC - F03D 7/0284: {in relation to the state of the electric grid} - H02P 9/00: Arrangements for controlling electric generators for the purpose of obtaining a desired output - F03D 9/255: {connected to electrical distribution networks; Arrangements therefor} - H02H 9/001: {limiting speed of change of electric quantities, e.g. soft switching on or off (progressive control of electronic switches for eliminating interferences H03K17/16)} - H02M 1/36: Means for starting or stopping converters - H02P 9/006: {Means for protecting the generator by using control (control effected upon generator excitation circuit to reduce harmful effects of overloads or transients H02P9/10)} - H02P 9/007: {Control circuits for doubly fed generators} - H02P 9/08: Control of generator circuit during starting or stopping of driving means, e.g. for initiating excitation - H02P 9/102: {for limiting effects of transients} - F05B 2220/70646: Double fed induction generators (DFIGs) - F05B 2270/337: Electrical grid status parameters, e.g. voltage, frequency or power demand - H02P 2101/15: for wind-driven turbines - Y02E 10/72: Wind turbines with rotation axis in wind direction - Y02E 10/76: Power conversion electric or electronic aspects - F03D: WIND MOTORS - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS - H02H: EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS (indicating or signalling undesired working conditions G01R, e.g. G01R31/00, G08B; locating faults along lines G01R31/08; emergency protective devices H01H) - 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) - F05B: INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A method for a method for minimizing inrush of current during start-up of an alternating current (AC) electrical power system connected to a power grid includes determining a grid voltage of the power grid. The method also includes charging an AC capacitance of a grid filter of the electrical power system from an initial capacitance value to a predetermined percentage of the grid voltage. Further, the method includes connecting the electrical power system to the power grid when the AC capacitance in the grid filter reaches the predetermined percentage of the grid voltage. Moreover, the method includes initiating start-up of the electrical power system. ## Claims ### Claim 1 A method for minimizing inrush of current during start-up of an alternating current (AC) electrical power system connected to a power grid, the method comprising: determining a grid voltage of the power grid; charging an AC capacitance of a grid filter of the electrical power system from an initial capacitance value to a predetermined percentage of the grid voltage; connecting the electrical power system to the power grid when the AC capacitance in the grid filter reaches the predetermined percentage of the grid voltage; and, initiating start-up of the electrical power system. ### Claim 2 (depends on 1) The method of claim 1, further comprising charging the AC capacitance in the grid filter of the electrical power system with at least one additional electrical component coupled to the grid filter, the at least one additional electrical component comprising at least one of one or more resistors or a contactor. ### Claim 3 (depends on 2) The method of claim 2, further comprising bypassing the at least one additional electrical component after connecting the electrical power system to the power grid but before initiating start-up the electrical power system. ### Claim 4 (depends on 1) The method of claim 1, further comprising charging the AC capacitance in the grid filter of the electrical power system via a power converter of the electrical power system operating in a first operating mode, the power converter configured to produce a voltage in sync with the grid voltage prior to connecting the electrical power system to the power grid. ### Claim 5 (depends on 4) The method of claim 4, further comprising charging a DC link of the power converter to a predetermined power level prior to charging the AC capacitance in the grid filter of the electrical power system via the power converter. ### Claim 6 (depends on 4) The method of claim 4, further comprising supplying a DC link of the power converter with additional power prior to charging the capacitance in the grid filter of the electrical power system via the power converter. ### Claim 7 (depends on 4) The method of claim 4, further comprising transitioning from the first operating mode of the power converter to a second operating mode after charging the AC capacitance of the grid filter of the electrical power system, the first operating mode corresponding to an AC charging mode, the second operating mode corresponding to a standard operating mode. ### Claim 8 (depends on 1) The method of claim 1, wherein the predetermined percentage of the grid voltage comprises up to about 100% of the grid voltage. ### Claim 9 (depends on 1) The method of claim 1, wherein the electrical power system comprises at least one of a wind turbine power system or a solar power system. ### Claim 10 A wind turbine power system, comprising: a generator comprising a rotor and a stator; a power converter comprising a line-side converter coupled to a rotor-side converter via a DC link, the rotor-side converter coupled to the rotor; a grid filter coupled between the line-side converter and a power grid; a controller configured to control the wind turbine power system, the controller configured to perform one or more operations, the one or more operations comprising: charging the grid filter from an initial voltage value to a predetermined percentage of a grid voltage of the power grid; connecting the wind turbine power system to the power grid when the initial voltage value in the grid filter reaches the predetermined percentage of the grid voltage; and, initiating start-up of the wind turbine power system after the initial voltage value in the grid filter reaches the predetermined percentage of the grid voltage. ### Claim 11 An alternating current (AC) electrical power system, comprising: a generator comprising a rotor and a stator; a power converter comprising a line-side converter coupled to a rotor-side converter via a DC link, the rotor-side converter coupled to the rotor; a grid filter coupled between the line-side converter and a power grid; a controller configured to control the electrical power system, the controller configured to perform one or more operations, the one or more operations comprising: determining a grid voltage of the power grid; charging an AC capacitance of the grid filter from an initial capacitance value to a predetermined percentage of the grid voltage; connecting the electrical power system to the power grid when the AC capacitance in the grid filter reaches the predetermined percentage of the grid voltage; and, initiating start-up of the electrical power system. ### Claim 12 (depends on 11) The electrical power system of claim 11, wherein the one or more operations further comprise charging the AC capacitance in the grid filter with at least one additional electrical component coupled to the grid filter, the at least one additional electrical component comprising at least one of one or more resistors or a contactor. ### Claim 13 (depends on 12) The electrical power system of claim 12, wherein the one or more operations further comprise bypassing the at least one additional electrical component after connecting the electrical power system to the power grid but before initiating start-up of the electrical power system. ### Claim 14 (depends on 11) The electrical power system of claim 11, wherein the one or more operations further comprise charging the AC capacitance in the grid filter via the line-side power converter operating in a first operating mode, the line-side power converter configured to produce a voltage in sync with the grid voltage prior to connecting the electrical power system to the power grid. ### Claim 15 (depends on 14) The electrical power system of claim 14, wherein the one or more operations further comprise charging the DC link of the power converter to a predetermined power level prior to charging the AC capacitance in the grid filter of the electrical power system via the line-side power converter. ### Claim 16 (depends on 14) The electrical power system of claim 14, further comprising transitioning from the first operating mode of the line-side converter to a second operating mode after charging the AC capacitance of the grid filter, the first operating mode corresponding to an AC charging mode, the second operating mode corresponding to a standard operating mode. ### Claim 17 (depends on 15) The electrical power system of claim 15, wherein the one or more operations further comprise supplying the DC link with additional power prior to charging the capacitance in the grid filter of the electrical power system via the line-side power converter. ### Claim 18 (depends on 11) The electrical power system of claim 11, wherein the predetermined percentage of the grid voltage comprises up to about 100% of the grid voltage. ### Claim 19 (depends on 11) The electrical power system of claim 11, wherein the electrical power system comprises at least one of a wind turbine power system or a solar power system. ### Claim 20 (depends on 11) The electrical power system of claim 11, wherein the electrical power system comprises a doubly-fed induction generator (DFIG).