An active-power filter includes control circuitry to combine an integrated output-voltage
feedback signal, an input-voltage sense signal and an output-load feedforward signal
to generate a control signal. An output-load subsystem draws the output current
from the active-power filter and the output-load feedforward signal indicates when
current drawn by an output-load subsystem changes. In some embodiments, the output-load
subsystem may draw output current from the power converter having an output current
ripple at a nominal frequency, which may range, for example, between about 35 and
100 Hz. The control circuitry may include an integrator to integrate the output-voltage
feedback signal. The integrator may have a control loop bandwidth significantly
less than the nominal ripple frequency to loosely regulate the output voltage while
the input current drawn by the active-power filter is tightly regulated.