Abstract: A control system for controlling the operation of a doubly fed induction generator of an electrical power system, such as a wind turbine, is provided. A rotor side converter coupled to a rotor of the DFIG is controlled by the control system. The control system includes an outer controller to generate a reference value for a control variable in accordance with which the operation of the DFIG is to be controlled and an inner controller that receives the reference value and provides feedback control of the rotor side converter. The inner controller is a state feedback controller obtains at least one state of the power system or the power grid that is different from the control variable. The control structure of the state feedback controller causes the electrical power system to act as a passive system at least in a predefined frequency range.

Abstract: A control method for the rotor side converter of a doubly-fed induction generator in a wind turbine for disturbances in the electric grid is provided. A control system includes 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, where the current controller is configured to operate with a modulation index being outside a linear area and a second operating mode, set during a stable state of the disturbance in the electric grid, where the current controller is configured to operate with a modulation index inside the linear area, thereby instantly providing a maximum voltage available in a rotor so as to satisfy the at least one reference current.

Abstract: A three phase medium voltage power conversion system for closed-loop applications comprising a 3L-NPC converter. The switching system of the 3L-NPC converter is based on SHE-PWM patrons. The regulation system of the 3L-NPC converter comprises a controller and an interface module between the controller and the switching system which is configured for supplying to the switching system voltage reference samples at a rate L times faster than the rate of voltage reference samples managed by the controller.

Abstract: The invention provides a three phase medium voltage power conversion system for coupling a power source to a utility grid comprising a power converter and a Notch-Filter. The switching control system of the inverter of the power converter is based on SHE-PWM patrons. The Notch-Filter is tuned to attenuate the frequency of the first harmonic that the switching control system of the inverter cannot attenuate and configured with damping means capable of smoothing the resonance frequency without affecting the notch frequency.

Abstract: The invention provides a three phase medium voltage power conversion system for coupling a power source to a utility grid comprising a power converter and a Notch-Filter. The switching control system of the inverter of the power converter is based on SHE-PWM patrons. The Notch-Filter is tuned to attenuate the frequency of the first harmonic that the switching control system of the inverter cannot attenuate and configured with damping means capable of smoothing the resonance frequency without affecting the notch frequency.

Abstract: A three phase medium voltage power conversion system for closed-loop applications comprising a 3L-NPC converter. The switching system of the 3L-NPC converter is based on SHE-PWM patrons. The regulation system of the 3L-NPC converter comprises a controller and an interface module between the controller and the switching system which is configured for supplying to the switching system voltage reference samples at a rate L times faster than the rate of voltage reference samples managed by the controller.