Performance Comparison of Different Buck-Boost Converters for Power Factor Correction in an SMPS for PC Applications

In the conventional power supplies used for PC applications, the supply current’s Total Harmonic Distortion (THD) ranges up to 80%, and the power factor goes as low as 0.55. When a large number of such power is used for powering up many electronic appliances, the power quality of the distribution system deteriorates drastically, simultaneously increasing the neutral current considerably. This affects the performance parameters and efficiency of the distribution system adversely. This paper aims to provide an improved model of SMPS (Switched Mode Power Supply) with a power factor correction stage, which could look into the reduction of harmonic content and improve the quality of supply. Three types of buck-boost converters are explored here, namely, a conventional buck-boost, Cuk and SEPIC, which are employed for PFC. All three converters have been analyzed, and their design equations are derived and used to design each component in these converters in Discontinuous Conduction Mode (DCM). Then each one of them has been modeled in MATLAB-Simulink environment. The performance of the modeled power supply with three different types of PFC converters is compared in terms of settling time, overshoot, power factor, and current harmonic content at the utility interface point stress across the devices, number of components and capability to regulate the voltage output during supply voltage and load variations. From this objective comparison, it would be easy for any user to make a judicious choice for the SMPS application as per the user requirements.