2015 IEEE Interational Conference on Technological Advancements in Power & Energy Two Switch Buck Boost Converter for Power Factor Correction Chita Chandran Dept. of Electical & Electonics Amrita School of Engineering Amritapuri, Kollam, INDIA chitaabhilash@yahoo.com Abstract- Now-a-days the usage of power electronic systems has expanded to new and wide application range but the presence of harmonics is a major problem. The nonlinear operation of power semi converters and presence of bridge rectifers in electronic devices for AC-DC conversion resulted in a high Total Harmonic Distortion (THD) and low Power Factor (PF). Thus there arise the need for a power factor correction circuit along with the power converters for limiting the allowable harmonics on the power lines, and hence to improve the power factor. This paper aims to develop an active power factor correction (PFC) for single phase AC/DC converter, along with a Two Switch Buck- Boost converter. The converter is designed for a load of IkWat220V. Inde Terms-Two Switch Buck Boost, Power Factor Correction, Two Mode Control Scheme. I. INTRODUCTION Now a day with increasing use of power converter devices and power electronic loads, more emphasis is given to power factor correction (PFC) and reduction in total harmonic distortion (TH) in the current drawn fom the power utility. In order to improve the power quality, researchers have given more attention on development of new topologies on power converter. Improvements can be achieved by PFC techniques. Since now, various passive and active power factor correction circuits have been proposed, of which active power factor circuits found to be more advantageous. Thus active PFC techiques have rapidly become a vigorous research topic in the power electronics feld and eforts have been made on the development of the PFC converters [1]. Various power factor correction (PFC) techiques for buck converter, boost converter, buck boost converter topologies are employed to overcome the power quality problems. This paper proposes a Two Switch Buck Boost converter along with a power factor correction contol to improve the power factor and hence reduce the TH. Two switch buck boost converter have the ability of both step up and step down with low voltage stress when compared with the basic converter. These converters have two switches, Ql and Q2 which are operated independently [2]. A two mode control scheme is discussed in this paper. I this scheme when input voltage is greater than the output voltage Q2 is always kept off and pulse signals to Q, is contolled to regulate the output voltage then TSBB converter is equivalent to a buck 978-1-4799-8280-6/15/$3l. 00 ©2015 IEEE Lekshmi R. Chandran Dept. of Electical & Electonics Amrita School of Engineering Amritapuri, Kollam, INDIA lekshmichandran@am.amrita.edu converter and when input voltage is less than the output voltage QJ is always kept on and Q2 is contolled to regulate the output voltage then TSBB converter is equivalent to a boost converter. II. CONTROL STRTEGIES FOR PFC IN AC/DC CONVERTERS For one stage PFC converters, the main challenge is the availability of only one contol variable to perform voltage regulation and power factor correction in a single step. As a result, in the design of the contoller, a tadeof needs to be considered between outut voltage regulation and power factor correction. For single-stage PFC converters many contol techiques have been designed [3]-[8] which are classifed as follows. 1. Peak current contol 2. Hysteresis current control 3. Average current-mode contol Each of these contol techiques is explained briefy below 1. Peak Current Contol In Peak Current Contol, the positive slope of the inductor current is contolled so that it is equal to a reference value in each switching cycle. The inductor current increases when the switch is on, till instantaneous current reaches the reference value and then the switch is tued off The product of the voltage compensator output and the sensed input voltage gives the sinusoidal current reference, and it is used to keep the input current in phase with the input voltage. Absence of current compensator for the contoller and constant switching fequency is the peculiarity of this scheme. Such a contol scheme is shown in fg. 1. Fig.l. Peak current control 454