Design and implementation of high performance switch mode boost converter
Abstract

Boost converter is a dc-to-dc converter that steps up the dc voltage from its fixed low level to a desired high level. It is also called the fly-back converter because the energy transfer, from the source to the load, takes place only during the off period of the switch.
DC power supplies are extensively used inside most of electrical and electronic appliances in the world today, such as in computers, monitors, televisions, audio sets and others. There are commonly known as rectifiers. The nature of rectifiers either it is conventional or switch mode types, all of them contribute to low PF, high THD and low efficiency to the power system. With the imposed of harmonic standards such as IEC 61000-3-2 by international communities, it would be much important aspect to consider in every design of the appliances.
.
Research into switch mode power factor corrected ac-dc converters has been in two directions namely buck and boost type topologies. The advantage of Buck type topology is that the converter can provide variable output voltage, which is lower than the input voltage. However, when the instantaneous input voltage is below the output voltage the current drops to zero and results in significant increase in input current THD.

Design of input filters for power factor improvement in buck converters is therefore complex and provides only limited improvement in input current quality. On the other hand the boost type converter generates dc voltage, which is higher than the input voltage. However, the input current in these converters flows through the inductor and therefore can easily be actively wave-shaped with appropriate current mode control. Moreover, boost converters provide regulated dc output voltage at unity input power factor and reduced THD of input ac current. These converters have found widespread use in various applications due to the advantages of high efficiency, high power density and inherent power quality improvement at ac input and dc output.
The process of shaping the input current is done by the Boost converter, which is properly controlled by the related circuitry. The control circuits for this project used low-cost components, easily available yet giving excellent performance and satisfactory results.