IJSRST173720 | Received : 26 Aug 2017 | Accepted : 03 Sep 2017 | September-October-2017 [(3) 7: 58-64] © 2017 IJSRST | Volume 3 | Issue 7 | Print ISSN: 2395-6011 | Online ISSN: 2395-602X Themed Section: Science and Technology 58 Design and Simulation of Closed Loop Controller for SEPIC Converter to Improve Power Factor R. Jai Ganesh *1 , A. Bhuvanesh 2 * 1 Department of EEE, K. Ramakrishnan College of Technology, Tiruchirapalli, Tamil Nadu, India 2 Department of EEE, Mepco Schlenk Engineering College, Sivakasi, Tamil Nadu, India ABSTRACT One of the solid state switch mode rectification converters is SEPIC converter. This paper presents the design, simulation and development of single phase AC-DC SEPIC converter with 1.5W output power. The non-isolated SEPIC converter is performed in this paper. The control techniques such as voltage follower control, average current control with voltage follower, borderline control technique are implemented to improve the overall power factor and to reduce Total Harmonic Distortion. Keywords: Single switch buck-boost SEPIC converter, Control techniques, L-C input filter I. INTRODUCTION Power electronic converters are a family of electrical circuits which convert electrical energy from one level of voltage/current/frequency to other using semiconductor based electronic switches. The essential characteristic of these types of circuits is that the switches are operated only in one of the two states, either fully ON or fully OFF, unlike other types of electrical circuits where the control elements are operated in a linear active region. The process of switching the electronic devices in a power electronic converter from one state to another is called modulation. The thyristorised power converters are referred to as the static power converters and they perform the function of power conversion by converting the available input power supply into output power of desired form. The different types of thyristorised power converters are diode rectifiers, line commutated converters, AC voltage controllers, cycloconverters, DC choppers and inverters. The conventional technique of single phase ac-dc conversion using a diode bridge rectifier with dc filter capacitor results in poor power quality in terms of injected current harmonics, voltage distortion, poor power factor at input ac mains, slow varying rippled dc output at load end, low efficiency and large size of AC and DC filters. A low power factor reduces the real power available from the utility grid, while a high harmonic distortion of line current causes Electro Magnetic Interference problems and cross interferences. They do not comply with the international regulations governing the power quality. Solid state switch mode rectification converters have the ability to improve the power quality of AC mains and regulate DC output in buck, boost, and buck-boost modes. Improvements in power factor and reduction in harmonic distortion can be achieved by modifying the stage of the diode rectifier’s filter capacitor circuit. Several power factor correction (PFC) topologies are conceived [1]. Normally AC-DC conversion is carried out by simply rectifying the AC input and the rectified output is filtered by means of a large value of capacitance to get a nearly constant DC output voltage. In this conversion, the input AC supply current is drawn in narrow pulses since the capacitor voltage variation is nearly constant. This narrow pulse current of high peak, results in power quality problems to nearby consumers, which include higher value of Total Harmonic Distortion (THD) on supply current, higher THD of input supply voltage, lower value of power factor and displacement factor and poor distortion factor [2]. These large harmonic currents are undesirable because they not only produce distortion of AC line voltage but also result in conducted and radiated electromagnetic interference. The problem becomes more serious particularly when several drive units are connected to single-phase supply where the input power pulsates at twice the frequency. The simulation and implementation of closed-loop controllers for a single phase AC-DC three-level LED