A Multi-Mode Variable-Frequency Discrete Control for Boost PFC Converter

This paper proposes a multi-mode variable-frequency discrete control over a universal input voltage range of 90–240 V ac to achieve low total harmonic distortion (THD) and high power factor (PF) in boost power factor correction (PFC) converters operating in discontinuous conduction mode (DCM), mixed conduction mode (MCM) and continuous conduction mode (CCM). Based on the input voltage and load conditions, the control method determine parameters of the CCM/MCM/DCM variable-frequency functions FCCM <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\left(\mathrm{I}_{o}\right)/\mathrm{F}_{\text {MCM }}\left(\mathrm{I}_{o}\right)/\mathrm{F}_{\text {DCM }}\left(\mathrm{I}_{o}\right)$</tex> respectively. The control method adaptively adjust switching frequency between 32-75kHz according to the conduction mode to ensure smooth mode transitions. Simulation results are provided, which show that high PF (0.988–0.999) and low THD (1%–16%) can be maintained over a wide input voltage range of 90–240 V ac and output power range of 30–1000W.