Experimental analysis and comparison on a power factor controller including a delta-sigma processing stage

Monolithic ICs allow simple and cheap single-phase power factor correction (PFC) systems to be implemented. They contain an analog multiplier, the transfer characteristic of which may be nonlinear. In this paper, the delta-sigma (ΔΣ) modulation technique is applied to fully implement the algebraic operations of a PFC system´s multiplier block. A ΔΣ multiplier prototype was breadboarded and inserted in a PFC control loop based on a commercial IC. The experimental results regarding the AC line current distortion are reported and compared with those obtained from the built-in analog multiplier of the IC. The benefits on the total harmonic distortion (THD) on the AC side are highlighted