A Boost PFC Converter With Programmable Harmonic Resistance

Power factor correction (PFC) converters with low harmonic input resistance are desirable loads to support the reduction of the harmonic distortion on the feeding grid. Therefore, a novel control strategy is proposed. Whereas previously proposed controllers tried to obtain a resistive behavior of the converter with a constant input impedance for all frequencies, including the fundamental, the proposed control strategy allows to set a harmonic input resistance which is independent of the input power level of the converter. Consequently, the harmonic input resistance remains low, even when the input power of the converter is decreased, which adds to the stability of the feeding grid. This paper describes the operation of a digitally controlled boost PFC converter with the new control algorithm. Experimental tests on a 1-kW prototype show that a practical realization of the algorithm is possible and that a programmable harmonic input resistance of the converter is obtained. The converter contributes to the damping in the power system, which is an important feature to mitigate harmonic voltage distortion due to resonances. The damping potential of the converter with the proposed control strategy is demonstrated on a scale model of a distribution system with a parallel resonance