Patent ID: 9041234
Filing Date: 2015-05-26
Classification: F03D,H02H,H02J,H02P,Y02E

Abstract:
1. A power conversion system for a double fed induction generator (DFIG), comprising: a rotor side converter comprising a plurality of AC connections coupleable to rotor leads of the DFIG and a plurality of DC connections coupled with a DC circuit, the rotor side converter comprising a rotor side rectifier circuit and a rotor side switching circuit, wherein the rotor side converter is operative when a rotor speed of the DFIG is above a nominal value to provide power from the rotor leads to the DC circuit using the rotor side rectifier circuit, and wherein the rotor side converter is operative when the rotor speed is below the nominal value to provide power from the DC circuit to the rotor leads using the rotor side rectifier circuit; a grid side converter comprising a plurality of DC connections coupled with the DC circuit and a plurality of AC connections coupleable to stator leads of the DFIG, the grid side converter comprises a grid side rectifier circuit and a grid side switching circuit, wherein the grid side converter is operative when the rotor speed is above the nominal value to provide power from the DC circuit to the stator leads using the grid side switching circuit, and wherein the grid side converter is operative when the rotor speed is below the nominal value to provide power from the stator leads to the DC circuit using the grid side rectifier circuit; a series damping apparatus coupled in series between the rotor leads of the DFIG and the grid side converter, the series damping apparatus comprising at least one series damping circuit including a series damping circuit resistance coupled in series between one of the rotor leads of the DFIG and the grid side converter, and a series damping switching circuit coupled in parallel with the series damping circuit resistance, the series damping switching circuit operative in a first mode to bypass the series damping circuit resistance to prevent current flow in the series damping circuit resistance and in a second mode to allow current to flow in the series damping circuit resistance; and a damping controller operative to control the mode of the series damping switching circuit based at least partially on a grid fault occurrence or a grid fault clearance.