An improved single stage phase Shifted control based ac dc power Factor correction converter

Abstract

The power distribution line problems such as ripples, harmonics and power factor has paved significant interest to researchers for improvisation of algorithms and circuit designs in power converters and inverters. The nonlinear loads cause ripple voltage across the power electronic circuits and results in distorted voltage, line current and reduces power factor in the supply. The ripples increase power loss, and results in low efficiency. Till now, many passive and active Power Factor Correction (PFC) techniques has been proposed by the researchers to improve the power factor in converters. Among them, passive filters have many limitations such as fixed compensation and large size, whereas the active power factor correction techniques are used due to their performance in terms of size and variable compensation. Switched Mode Power Supply (SMPS) is an active PFC and corrects the poor power factor and reduces the high harmonic current. An ideal PFC is used for input current shaping and maintains a regulated output voltage. In the case of sinusoidal line voltage, the PFC must draw a sinusoidal current from the utility through the suitable sinusoidal current reference and the control objective of PFC is to force the input current to follow current reference, as close as possible. In this thesis, an array of control techniques for PFC in DC-DC boost converter for single phase system is proposed through Modified Continuous Conduction Mode (MCCM). The boost features in AC-DC and DC-DC single stage converter are used for instantaneous input current shaping, and output voltage regulation. The boost features provide an output voltage that depends on the duty ratio with a polarity opposite to that of the input voltage, makes the boost converter as an inverting regulator newline newline newline