Abstract: 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.

Abstract: 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.

Abstract: The invention concerns a washing composition for washing a surface to deposit thereon substantially water-insoluble particles. The aqueous washing composition of the invention comprises an anionic surfactant, the particulate substance to be deposited and a water-soluble cationic non-cellulosic polymer which enhances the deposition of the particulate substance onto the surface but which cationic polymer does not form in the composition a water-insoluble complex with the anionic surfactant, the cationic charge density of the polymer being from 0.0001 to 0.0017; the concentration of the cationic polymer in the washing composition being from 0.0001% to 0.01% by weight; and the concentration of the surfactant in the washing composition being from 0.01% to 5% by weight.