Strategy for Current Harmonic Reduction of PFC with Boundary Control Using Second-order Switching Surface

The difference between the fast dynamics associated with the input current of power factor correctors (PFCs) and the slow dynamics associated with their output voltage is typically exploited by using multiple control loops. The overall dynamic response is generally limited by the output voltage regulation loop. Research into an analogy-based controller for PFCs is at a slow pace. This paper applies the concept of the boundary control method with a second-order switching surface for the boost type PFC, so as to achieve fast dynamic response. The method is based on predicting the state trajectory movement after a hypothesized switching action and the output can ideally be reverted to the steady state in two switching actions during the large-signal input voltage and output load disturbances. Besides, there is another control loop to compensate the error for the capacitor aging. Theoretical predictions are verified with the experimental results of a 300 W, 110 V prototype.