Control of energy flow from an electric machine with unbalanced impedance

摘要

A method for controlling an energy flow to a grid, from an electrical alternating current machine with unbalanced impedance, in particular an electrical alternating current generator of a wind turbine, the method comprising: obtaining a first power signal (P1) representing a first power command; obtaining a second power signal (P2) representing a second power command; obtaining a first current signal (I1) indicative for a feedback current from the electrical alternating current generator; obtaining a second current signal (12) indicative for a feedback current from a grid converter; determining a first internal signal (int1) as a result from a first current reference calculation procedure (crc1) making use of the first power signal (P1), the first internal signal (int1) corresponding to a current command for the electrical alternating current machine; determining a second internal signal (int2) as a result from a second current reference calculation procedure (crc2) making use of the second power signal (P2), the second internal signal (int2) corresponding to a current command for the grid converter; determining a first output signal (OUT1) as a result from a first current controller procedure (cc1) making use of the first current signal (I1) and the first internal signal (int1), the first output signal (OUT1) representing a voltage command for a first axle of a machine synchronous rotating frame, the voltage command for the first axle being applicable for controlling the energy flow from the electrical alternating current machine; and determining a second output signal (OUT2) as a result from a second current controller procedure (cc2) making use of the second current signal (12), the second internal signal (int2) and a compensation calculation procedure, the second output signal (OUT2) representing a voltage command for a second axle of the grid synchronous rotating frame, the voltage command for the second axle being applicable for controlling the energy flow from the electrical alternating current machine.