Abstract
The current-fed high-power-factor converters (buck and buck-boost converters) have several advantages, such as no lower-limit of the output-voltage control range and no rush-current of the input-current. However, the single-phase current-fed high-power-factor converter with PWM (Pulse-Width-Modulation) produces undesirable lower order harmonics in the input-current. Thus, the PWM requires a bulky and costly inductor connected in the dc-side of the current-fed converter to reduce the dc-inductor-current ripples. To overcome the problem, the authors have proposed PSM (Pulse-Space-Modulation).
This paper describes a comparison of the characteristics (THDi (Total Harmonic Distortion of the input-current), the power factor and reducing dc-inductor's inductance) between buck and buck-boost high-power-factor converters with PSM. The buck-boost converter has many advantages over the buck converter in the input-current waveform, power factor and reducing dc-inductor's inductance. To illustrate the validity of the theory, experimental results obtained from a 1.2[kW] setup and computer simulation results are shown.
