# US 8,786,119 B2 · Electric generator control system and method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,786,119 B2 - Document ID: US8786119B2 - Status: Granted - Kind: B2 - Application number: 13/643,904 - Filed: 2010-04-29 - Published: 2013-08-08 - Granted: 2014-07-22 - Earliest claimed: 2010-04-29 - Assignees: Ingeteam Power Technology, S.A. - Applicants: David Sole Lopez; Iker Garmendia Olarreaga; Javier Coloma Calahorra; Jesús Mayor Lusarreta; Josu Elorriaga Llanos; Ainhoa Carcar Mayor - Inventors: David Sole Lopez; Iker Garmendia Olarreaga; Javier Coloma Calahorra; Jesús Mayor Lusarreta; Josu Elorriaga Llanos; Ainhoa Carcar Mayor - Web page: https://patentgrep.com/patent/US8786119B2 ## CPC - F03D 7/00: Controlling wind motors (supplying or distributing electrical power H02J, e.g. arrangements for adjusting, eliminating or compensating reactive power in networks H02J3/18; controlling electric generators H02P, e.g. arrangements for controlling electric generators for the purpose of obtaining a desired output H02P9/00) - H02P 9/007: {Control circuits for doubly fed generators} - H02P 9/102: {for limiting effects of transients} - Y02E 10/72: Wind turbines with rotation axis in wind direction - F03D: WIND MOTORS - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract The invention describes a system and a method for controlling an electric generator connected to the power grid during a voltage drop in the power grid, the system comprising a back-to-back converter (2) connected between the generator (3) and the power grid (4) and also, in parallel to the generator side converter (2a), rectifying means (5) connected in series between the generator (3) and the DC-link (2b) of the back-to-back converter (2), thus providing an alternative way for the energy excess at the generator side to enter the DC-link (2b). ## Claims ### Claim 1 An electric generator control system comprising: a back-to-back converter adapted to be connected between a generator and a power grid, the back-to-back converter comprising a generator side converter, and a DC-link connected in series, a rectifying unit connected in parallel to the generator side converter and connected in series to the DC-link, and, a semiconductor unit comprising a first thyristor, connected in series between a positive pole of the DC-link and a DC output of the rectifying unit, and a second thyristor connected in series between a negative pole of the DC-link and a DC output of the rectifying unit. ### Claim 2 (depends on 1) The electric generator control system according to claim 1, wherein the rectifying unit comprises a bridge comprising one of a diode, an insulated-gate bipolar transistor, and a thyristor. ### Claim 3 (depends on 2) The electric generator control system according to claim 2, wherein the rectifying unit is connected to a rotor of the generator. ### Claim 4 (depends on 2) The electric generator control system according to claim 2, wherein the rectifying unit is connected to a stator of the generator. ### Claim 5 (depends on 2) The electric generator control system according to claim 2, further comprising a resistive dissipation unit connected to the DC-link. ### Claim 6 (depends on 1) The electric generator control system according to claim 1, wherein the rectifying unit is configured to be connected to a rotor of the generator. ### Claim 7 (depends on 6) The electric generator control system according to claim 6, wherein the rectifying unit is connected to a stator of the generator. ### Claim 8 (depends on 6) The electric generator control system according to claim 6, further comprising a resistive dissipation unit connected to the DC-link. ### Claim 9 (depends on 1) The electric generator control system according to claim 1, wherein the rectifying unit is configured to be connected to a stator of the generator. ### Claim 10 (depends on 9) The electric generator control system (1) according to claim 9, further comprising a resistive dissipation unit connected to the DC-link. ### Claim 11 (depends on 1) The electric generator control system according to claim 1 further comprising a resistive dissipation unit connected to the DC-link. ### Claim 12 (depends on 1) A wind power generator comprising: a generator; and the generator control system according to claim 1. ### Claim 13 A method for controlling an electric generator connected to a power grid by a back-to-back converter comprising a generator side converter and a DC-link connected in series, the method comprising: connecting a rectifying unit in parallel to the generator side converter and in series to the DC-link, connecting a semiconductor unit comprising a first thyristor, connected in series between a positive pole of the DC-link and a DC output of the rectifying unit, and a second thyristor, connected in series between a negative pole of the DC-link and a DC output of the rectifying unit, and in response to a voltage drop in the power grid, controlling the rectifying unit to conduct an energy excess in the generator towards the DC-link. ### Claim 14 (depends on 13) The method for controlling an electric generator according to claim 13 further comprising: driving the semiconductor unit to enable the energy excess to flow through the rectifying unit towards the DC-link. ### Claim 15 (depends on 13) The method of claim 13, wherein the semiconductor unit comprises a plurality of thyristors, and wherein the driving the semiconductor unit comprises a control system driving the semiconductor unit at a time selected by the control system. ### Claim 16 (depends on 13) The method of claim 13, wherein the driving the semiconductor unit comprises enabling the excess energy to flow to the power grid through a grid-side converter of the back-to-back converter. ### Claim 17 (depends on 13) The method of claim 13, further comprising connecting a capacitive dissipation unit to the DC-link, and wherein the method further comprises the capacitive dissipation unit absorbing the excess energy and releasing the excess energy once the power grid has recovered from the voltage drop. ### Claim 18 (depends on 13) The method according to claim 13, further comprising: providing the electrical generator and the back-to-back converter.