Stability analysis of a series active filter integrated with adouble-series diode rectifier

摘要

This paper deals with a harmonic current-free AC/DC powernconversion system which is characterized by the integration of ansmall-rated series active filter with a large-rated double-series diodenrectifier. The stability of the active filter based on feedback controlnis discussed theoretically, taking into account delay time in thencontrol circuit. As a result, it is revealed that the delay time maynproduce a bad effect on stability, especially when the power conversionnsystem is installed on a stiff power system with low system inductance.nThe authors propose a viable way of reducing the effect of delay time onnthe system stability. Analysis in the frequency domain enables us tonknow how much the system stability is improved in terms of gain andnphase margins. A switching-ripple filter is designed to obtain goodnfiltering performance without affecting the system stability.nExperimental results obtained from a 20 kW laboratory system verify thenvalidity of the developed theory, and confirm the viability andneffectiveness of the proposed control circuit