Abstract: A controller-implemented method and system for operating a multi-level bridge power converter connected to a power grid in a fault-tolerant operational mode, the power converter including a first converter coupled to a DC link, the first converter including a plurality of switching devices. The method and system determine an on/off scheme for the switching devices in the first converter when one or more of the switching devices has failed in a shorted state, wherein the on/off scheme is dependent upon phase current direction through the first converter. The phase current direction is indirectly determined by sensing a pole voltage of the first converter and implementing the on/off scheme in the fault-tolerant mode when the pole voltage changes from zero to a +/?value indicating that the phase current through the first converter has switched direction.

Abstract: A method for controlling an active harmonic filter of an inverter-based resource includes receiving, via a maximum compensation tracker module, a grid feedback signal, determining, via the maximum compensation tracker module, a phase shift signal based, at least in part, on the grid feedback signal, applying, via the maximum compensation tracker module, a phase shift offset signal to the phase shift signal to obtain a modified phase shift signal, determining, via the maximum compensation tracker module, a voltage reference signal for the active harmonic filter based, at least in part, on the grid feedback signal and the modified phase shift signal; and controlling, via the maximum compensation tracker module, the active harmonic filter using the voltage reference signal, wherein the phase shift offset signal ensures that the active harmonic filter injects a current substantially out of phase of a targeted harmonic.

Abstract: A method for operating a power supply system connected to a grid, the power supply system including a rotor, a doubly-fed induction generator (DFIG), a power conversion assembly, and an active filter. The DFIG includes a generator rotor mechanically connected with the rotor and a generator stator. The power conversion assembly includes a rotor-side power converter. The active filter electrically connected with the generator stator via a stator bus and the rotor-side power converter electrically connected with the generator rotor via a rotor bus. Based on a rotor frequency of the generator rotor, the method determines an expected harmonic frequency for a stator current flowing on the stator bus. An amplitude of the stator current at the expected harmonic frequency is determined via a data set of stator current values. The method controls the active filter based on the amplitude of the stator current at the expected harmonic frequency.

Abstract: A controller-implemented method and system for operating a multi-level bridge power converter connected to a power grid in a fault-tolerant operational mode, the power converter including a first converter coupled to a DC link, the first converter comprising a plurality of switching devices. The method and system determine an on/off scheme for the switching devices in the first converter when one or more of the switching devices has failed in a shorted state, wherein the on/off scheme is dependent upon phase current direction through the first converter. The phase current direction is indirectly determined by sensing a pole voltage of the first converter and implementing the on/off scheme in the fault-tolerant mode when the pole voltage changes from zero to a +/?value indicating that the phase current through the first converter has switched direction.