Patent ID: 8957535
Filing Date: 2015-02-17
Classification: F03D,F05B,H02J,H02M,Y02E,Y02P

Abstract:
1. A method of generating and converting electrical energy using a wind turbine, the wind turbine including a generator and an electric-converter system and being configured to operate in a fully-functional converter mode and a faulty-converter mode; the electric-converter system being configured to, using electric power generated by the generator, convert and supply electric power at a nominal active power to a point of common coupling of the wind turbine to an electrical grid; the electric-converter system including a plurality of parallel converters dimensioned to provide a nominal active-current corresponding to the nominal active power, each of the converters also having an over-current margin to enable an over-current to be produced in addition to the nominal active-current in the fully-functional converter mode; wherein the wind turbine further includes a converter-cooling system with a coolant having a coolant temperature, the converter-cooling system configured to cool the electric-converter system; wherein the converters are also dimensioned to provide the nominal active-current at a predetermined coolant temperature; wherein less heat is produced by the converter system while operating in the faulty-converter mode than in the fully-functional converter mode, as less electric power is converted by the converter system in the faulty-converter mode than in the fully-functional converter mode; the method comprising: while operating in the fully-functional converter mode, causing one or more converters of the plurality of parallel converters to produce the over-current in addition to the nominal active-current; changing, in response to a fault of one or more of the converters of the plurality of parallel converters, operation of the wind turbine from the fully-functional converter mode to the faulty-converter mode; while operating in the faulty-converter mode: causing at least one other, non-faulty converter of the electric-converter system to produce additional active-current by using the over-current margin of the at least one other, non-faulty converter to compensate at least partly for a reduction of active-current production from the one or more faulty converters and to correspondingly reduce the over-current production produced by the one or more converters in the fully-functional converter mode; at least one of lowering the coolant temperature and detecting a lowered coolant temperature; and causing at least one other converter of the electric-converter system other than the one or more faulty converters to produce additional active-current using an increase to the over-current margin resulting from the lowered coolant temperature, to compensate at least partly for a reduction of active-current production due to the fault.