Reference governor for switching converters with power factor correction

It is increasingly common to require performance improvement for power converters without modifying the original integrated controller, due to the multiple uses a single converter can serve. Such a goal can be met with the design of a regulator for the pre-compensated system, which serves as an add-on to enable new features and tighter performance targets. That is usually addressed with a Reference Governor (RG). We present here the design of an RG algorithm for a single-phase AC-DC boost converter, which is already controlled by an integrated digital Power Factor Correction (PFC) module. The converter operates in continuous conduction mode, and unitary power factor is achieved by a standard cascaded proportional-integral control with input voltage feedforward. We show that the non-invasive RG algorithm can improve the total harmonic distortion, power factor and voltage regulation. The proposed approach is based on model predictive control and subspace identification of the closed-loop prediction model. Numerical results on a high-fidelity simulator for power electronics confirm the advantages of the approach.