Fault tolerant wind turbine converter

摘要

A wind turbine is arranged to operate in a fully-functional converter mode and a faulty-converter mode. A plurality of converters are arranged to share electric current in the fully-functional converter mode. The converters are dimensioned not only to operate at nominal active current but to provide an over-current margin to enable reactive current to be produced on top of the nominal active current in the fully-functional converter mode. In the fully-functional converter mode the converters are caused to produce reactive current on top of the nominal active current. In response to a fault of one or more of the converters, operation is changed from the fully-functional converter mode to the faulty-converter mode. In the faulty-converter mode, one or more other converters of the converter system are caused to produce additional active current by using their over-current margin to compensate at least partly for a reduction of active-current production due to the fault of one of the converters, and to reduce the reactive-current production by the other converter correspondingly.

主权项

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.