Control strategy for hybrid power filters based on current and voltage detection

What is it about?

A configuration consisting of a combination of a series active filter (APF) with a parallel passive filter has proven to be an efficient system for harmonic elimination of nonlinear loads. Themost effective strategy for this configuration determines the APF reference voltage as the addition of two terms, the first proportional to the source current harmonics and the second opposite to the load voltage harmonics, current and voltage detection (CVD). To obtain the first term, an adequate adjustment of the proportionality constant ‘k’ is necessary for the implementation of the control algorithm. In this paper, design criteria to obtain the k values have been established, based on the system state model. Analysis of the resulting model provides the information needed to establish design criteria for the control strategy, both in terms of harmonic filtering and system stability. Finally, an experimental prototype was developed. The usefulness of the compensation equipment is experimentally confirmed in two contrasting situations: sinusoidal supply voltages and distorted supply voltages.

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