Active power filters and methods control and regulate the input current drawn
from an electric power bus to a DC level. Load current fluctuations and ripple
current reflected back to the electric power bus are significantly reduced or substantially
eliminated. A switch mode power converter with a very low bandwidth output voltage
regulation control loop uses input voltage feedforward, output load feedforward,
and output voltage feedforward to provide a regulated DC input current significantly
attenuating input ripple current drawn from the electric power bus.