Active damping of synchronous grid oscillations using partial power converter

An oscillation damping system comprising:

• an oscillation detection circuit configured to detect a sub-harmonic oscillation in current received through a phase of a n-phase supply line from a synchronous alternating current (AC) grid;
• a partial power converter;
• and
• a damping control circuit configured to cause the partial power converter to damp the sub-harmonic oscillation, wherein the partial power converter is configured to shunt a portion of the current away from a phase of a synchronous motor during at least a portion of an upper-half of the sub-harmonic oscillation.

An apparatus comprising:

• a partial power converter;
• and
• a controller configured to:
• detect a sub-harmonic oscillation in current received through a phase of a n-phase supply line from a synchronous alternating current (AC) grid, wherein the phase of the n-phase supply line is electrically coupled to a phase of a synchronous motor;
• and
• cause the partial power converter to damp the sub-harmonic oscillation via an addition of a compensation current generated by the partial power converter to the phase of the synchronous motor during at least a portion of a lower-half of the sub-harmonic oscillation, wherein the phase of the synchronous motor is configured to receive the compensation current in addition to the current received from synchronous AC grid.