Patent ID: 6950321

Claim:
A method of actively damping an L-C filter of an inverter having a plurality of control inputs and an alternating current multi-phase output, comprising the steps of: feeding back the phase voltages of the alternating current multi-phase output through corresponding band-pass filters tuned to the natural frequency of the L-C filter to create corresponding filter correction voltages; providing the filter correction voltages to corresponding regulating signals to modify the control inputs to the inverter; transforming the feedback phase voltages from AC domain to DC domain equivalents, comprising a d-axis element, a q-axis element, and a zero-axis element; generating a zero-sequence error signal based on the difference between the zero-axis element and a zero-axis reference signal; passing the zero-sequence error signal through a band-pass filter tuned to one-half the natural frequency of the L-C filter to create a zero-sequence correction voltage; and providing the zero-sequence correction voltage to a zero-sequence regulator to further modify the control inputs of the inverter, wherein the modified control inputs to the inverter enable compensating regulation and damping of the fundamental and imbalance characteristics of the alternating current multi-phase output.