CPC H02P 9/007 (2013.01) [H02P 2101/15 (2015.01)] | 13 Claims |
1. A control system for a rotor side converter of a doubly-fed induction generator in a wind turbine, the control system comprising:
a calculating unit configured for calculating at least one reference current;
a current controller which is a hybrid controller configured to operate in two different modes:
a first operating mode, set during a transient of a disturbance in an electric grid, wherein the current controller is configured to operate with a modulation index being above a linear boundary limit of the modulation index; and
a second operating mode, set during a state when current commands can be instantly reached, wherein the current controller is configured to operate with a modulation index below a linear boundary limit of the modulation index, thereby instantly providing a maximum voltage available in a rotor to achieve the at least one reference current;
wherein the current controller is also configured for simultaneously regulating a positive and a negative sequence of the rotor current; and
a sequence sensor configured for separately evaluating a voltage and current positive sequence and negative sequence, wherein the calculating unit is configured for calculating the at least one reference current as a function of the voltage and current positive sequences and negative sequences evaluated by the sequence sensor, wherein the calculating unit is also configured for calculating the at least one stator reference current as a function of the voltage and current positive sequence and negative sequence evaluated by the sequence sensor.
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