Abstract
This paper describes a new single-phase buck-boost Power-Factor-Correction (PFC) converter with outputvoltage-ripple-reducing operation. The converter consists of a conventional buck-boost PFC converter and an additional switch to obtain a freewheeling mode of the dc-inductor current, and is operated by two modulators. The first modulator controls the buck-boost switch to obtain PFC. The other modulator controls square-value of the instantaneous-dc-inductor-current to perform the output-voltage-ripple-reducing operation. In the two modulations, the time-integral-value of the input and output currents in each modulation period are controlled directly and indirectly, respectively. Thus, modulation errors or undesirable distortions of the input-current and output-voltage-ripple are eliminated even if the dcinductor-current produces large ripples in a low frequency range. The theories and combination techniques for the two modulators, implementation and experimental results are described.
