Optimal Set of Type-II dc Link Voltage Controller Coefficients for Practical Single-Phase Power Factor Correction Rectifiers Operating Under Grid Current Quality and Voltage Loop Stability Constraints

Type-II and proportional-integrative (PI) compensators are often employed as DC-link voltage controllers in practical single-phase power factor correction rectifiers (PFCRs). Corresponding controller coefficients are typically designed in frequency domain according to a rule-of-thumb imposing crossover frequency around 10 Hz, yielding unnecessarily high (>45°) phase margin. Recently, analytical guidelines for deriving PI controller coefficients set, allowing the system to comply with grid current total harmonic distortion (THD) and DC link voltage loop phase margin (PM) constraints, were established. This paper demonstrates that an additional degree-of-freedom (DOF) present in type-II compensator (compared to PI) permits optimizing DC-link voltage response to load step in addition to the above-mentioned constraints fulfilment. Design guidelines for deriving optimal type-II compensator coefficients set by means of combined time and frequency domain analysis are provided. The revealed findings are accurately supported by simulations and experiments.