Improved Power Factor In Bridgeless Converter by Fuzzy Controlled Based SMPS Applications

Abstract

power factor corrected (PFC) Switched Mode Power Supply (SMPS) based on bridgeless Buck-Boost converter topology with fuzzy logic control is proposed and is compared with the conventional SMPS. The multiple outputs of the SMPS are +12V,-12V, +5V,-5V for PC applications. To obtain nearly unity power factor and reduction in total harmonic distortion (THD) of input current, the SMPS with buck-boost converter based topology is designed to operate in discontinuous conduction mode (DCM). DCM operation gives added advantages of improved power factor and reduced switching losses and reduces the complexity of circuit operation. The presence of only two switches in the current conduction path during each switching cycle and the absence of diode bridge rectifier results in reduced conduction losses and an improved power factor, as compared to the conventional SMPS Single-phase ac supply is fed to a pair of back-to-back-connected buck–boost converters to eliminate the diode bridge rectifier, which results in reduction of conduction losses and power quality improvement at the front end. The operation of the bridgeless buck–boost converter in discontinuous conduction mode ensures inherent PFC operation and reduces complexity in control. To observe the performance of this converter, a model based on the Cuk topology has been designed and developed by using MATLAB/ SIMULINK software and implemented with Proportional-Integral (PI) and Fuzzy logic controller. The simulations are demonstrated in order to validate the effectiveness of the controllers in power factor improvement.