An approach to harmonic current-free AC/DC power conversion for large industrial loads: The integration of a series active filter with a double-series diode rectifier

This paper proposes a new harmonic current-free ac/dc power conversion system characterized by the integration of a small-rated series active filter with a large-rated double-series diode rectifier, The dc terminals of the active filter are directly connected in parallel with those of the diode rectifier, thereby forming a common dc bus, The active filter enables the diode rectifier to draw three-phase sinusoidal currents from the utility, In addition, it can provide the supplementary value-added function of regulating the common dc-bus voltage to a limited extent of +/-5%, slightly increasing the rms voltage rating, but not increasing the peak voltage rating. Experimental results obtained from a 5-kW laboratory system verify the practical viability and cost effectiveness of the proposed system.