A repetitive-based controller for a power factor precompensator

In this paper, a repetitive-based controller for a boost-based power factor precompensator is presented. The controller guarantees voltage regulation with a power factor close to unity, despite of the presence of harmonic distortion in the source voltage and uncertainties in the system parameters. It is shown that the repetitive scheme considered here is, in fact, equivalent to a bank of resonant filters, which has shown to be a useful technique in harmonic compensation. Out of this equivalence, a negative feedback structure is obtained for the repetitive scheme which is aimed for the compensation of odd harmonics only. This is in contrast to usual positive feedback repetitive schemes aimed to compensate for all harmonic components. The repetitive scheme consists on a simple feedback array involving a time delay plus a feedforward path, which is simple to implement. The closed-loop stability analysis of such and infinite-dimensional system is performed appealing to the well-known small gain theorem. Experimental results in a 400-W boost-based power factor compensator (PFC), with a fixed-point digital signal processor (DSP)-based implementation of the proposed controller, are provided to assess the performance of the controlled system.