Current-sensorless power factor correction with predictive controllers

Abstract

Power factor correction (PFC) converters are widely employed for ac/dc conversion to fulfill the applicable standards while ensuring high efficiency. Current-sensorless controllers in PFCs simplify the interaction between power and control circuits, improving noise immunity. This paper reviews the state-of-the-art in-line current control techniques, identifying relevant contributions that incorporate predictive algorithms and eliminate the current sensor. Furthermore, it evaluates two approaches for current-sensorless PFC. The first is applicable to converters with diode bridge and includes a high-resolution digital control loop to cancel the estimation errors. The second, valid for bridgeless PFCs, is a new current-sensorless control, which includes a fast compensation of the prediction errors with a third-harmonic-dependent function generated from a phase locked loop. This compensation modifies the duty cycle sequence obtained from the controller, ensuring the matching of the line current with the reference obtained from the line voltage. The two evaluated approaches are investigated via computer simulations and experimentally.