Improving the Dynamic Performance of the Commercial PFC Rectifiers by Compensation Network Redesign

This paper presents a simple method to improve the dynamic characteristics of on-shelf commercial PFC controllers, in particular reducing the DC link voltage undershoot (response to a step-like load power increase (US)) with an additional reduction of total harmonic distortion (THD). It is well known that a wide voltage loop bandwidth leads to a decrease in voltage undershoot, but may affect AC-side current quality. However, adding a notch filter in series with the existing voltage loop regulator prevents THD degradation. Guidelines to achieve the desired values of the two mentioned performance merits are provided for a commercial PFC rectifier board. Simulations and experimental results with modified 350W rated TI demo board PFC rectifier are also provided.