Flyback with Half Wave Rectifier for Single Stage Power Factor Correction K.Umamaheswari*, V.Venkatachalam ** *

Similar documents
Single Phase Converters for Power Factor Correction with Tight Output Voltage Regulation

SSRG International Journal of Electrical and Electronics Engineering (SSRG-IJEEE) volume 1 Issue 10 Dec 2014

Performance Improvement of Bridgeless Cuk Converter Using Hysteresis Controller

A Single Phase Single Stage AC/DC Converter with High Input Power Factor and Tight Output Voltage Regulation

Boost Converter for Power Factor Correction of DC Motor Drive

Implementation of Single Stage Three Level Power Factor Correction AC-DC Converter with Phase Shift Modulation

Webpage: Volume 3, Issue IV, April 2015 ISSN

Implementation of Single Stage Three Level Power Factor Correction AC-DC Converter with Phase Shift Modulation

WITH THE development of high brightness light emitting

A Novel Single-Stage Push Pull Electronic Ballast With High Input Power Factor

ZCS-PWM Converter for Reducing Switching Losses

AN EFFICIENT CLOSED LOOP CONTROLLED BRIDGELESS CUK RECTIFIER FOR PFC APPLICATIONS

Design and Simulation of New Efficient Bridgeless AC- DC CUK Rectifier for PFC Application

Linear Transformer based Sepic Converter with Ripple Free Output for Wide Input Range Applications

SINGLE STAGE SINGLE SWITCH AC-DC STEP DOWN CONVERTER WITHOUT TRANSFORMER

AC/DC Converter with Active Power Factor Correction Applied to DC Motor Drive

An Interleaved Single-Stage Fly Back AC-DC Converter for Outdoor LED Lighting Systems

A Novel Bridgeless Single-Stage Half-Bridge AC/DC Converter

POWER FACTOR CORRECTION USING AN IMPROVED SINGLE-STAGE SINGLE- SWITCH (S 4 ) TECHNIQUE

New Efficient Bridgeless Cuk Rectifiers for PFC Application on d.c machine

Comparative Analysis of Power Factor Correction Techniques for AC/DC Converter at Various Loads

IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 23, NO. 4, JULY

Soft-Switching Two-Switch Resonant Ac-Dc Converter

Analysis and Design of a Bidirectional Isolated buck-boost DC-DC Converter with duel coupled inductors

SINGLE STAGE LOW FREQUENCY ELECTRONIC BALLAST FOR HID LAMPS

International Journal of Scientific & Engineering Research, Volume 5, Issue 3, March-2014 ISSN

An Extensive Input Voltage and Fixed-Frequency Single Stage Series- Parallel LLC Resonant Converter for Dc Drive

A New Interleaved Three-Phase Single-Stage PFC AC-DC Converter with Flying Capacitor

A high Step-up DC-DC Converter employs Cascading Cockcroft- Walton Voltage Multiplier by omitting Step-up Transformer 1 A.Subrahmanyam, 2 A.

Controlled Transformerless Step-Down Single Stage AC/ DC Converter

Bridgeless Cuk Power Factor Corrector with Regulated Output Voltage

ENERGY saving through efficient equipment is an essential

ZCS BRIDGELESS BOOST PFC RECTIFIER Anna Joy 1, Neena Mani 2, Acy M Kottalil 3 1 PG student,

Integrated Buck-Buck-Boost AC/DC Converter

Closed Loop Control of the Three Switch Serial Input Interleaved Forward Converter Fed Dc Drive

Chapter 6 Soft-Switching dc-dc Converters Outlines

UNITY POWER FACTOR CORRECTION USING THE BI-BOOST TOPOLOGY WITH A FORWARD CONTROL TECHNIQUE

Power Factor Corrected Single Stage AC-DC Full Bridge Resonant Converter

MODERN switching power converters require many features

Page 1026

Hybrid Full-Bridge Half-Bridge Converter with Stability Network and Dual Outputs in Series

A New Single Switch Bridgeless SEPIC PFC Converter with Low Cost, Low THD and High PF

Neuro Fuzzy Control Single Stage Single Phase AC-DC Converter for High Power factor

Narasimharaju. Balaraju *1, B.Venkateswarlu *2

A HIGH STEP UP RESONANT BOOST CONVERTER USING ZCS WITH PUSH-PULL TOPOLOGY

Double Boost SEPIC AC-DC Converter

SCIENCE & TECHNOLOGY

ZVT Buck Converter with Synchronous Rectifier

Dynamic Performance Investigation of Transformer less High Gain Converter with PI Controller

Mitigation of Current Harmonics with Combined p-q and Id-IqControl Strategies for Fuzzy Controller Based 3Phase 4Wire Shunt Active Filter

High Frequency Soft Switching Of PWM Boost Converter Using Auxiliary Resonant Circuit

A NEW SINGLE STAGE THREE LEVEL ISOLATED PFC CONVERTER FOR LOW POWER APPLICATIONS

ZERO VOLTAGE TRANSITION SYNCHRONOUS RECTIFIER BUCK CONVERTER

A New Phase Shifted Converter using Soft Switching Feature for Low Power Applications

Controlled Single Switch Step down AC/DC Converter without Transformer

DC DC CONVERTER FOR WIDE OUTPUT VOLTAGE RANGE BATTERY CHARGING APPLICATIONS USING LLC RESONANT

High Frequency Isolated Series Parallel Resonant Converter

BIDIRECTIONAL dc dc converters are widely used in

Student Department of EEE (M.E-PED), 2 Assitant Professor of EEE Selvam College of Technology Namakkal, India

A HIGH EFFICIENT IMPROVED SOFT SWITCHED INTERLEAVED BOOST CONVERTER

Dual mode controller based boost converter employing soft switching techniques

DSP-BASED CURRENT SHARING OF AVERAGE CURRENT CONTROLLED TWO-CELL INTERLEAVED BOOST POWER FACTOR CORRECTION CONVERTER

[Singh*, 4(5): May, 2017] ISSN Impact Factor: 2.805

POWER ISIPO 29 ISIPO 27

Simulation and Performance Evaluation of Closed Loop Pi and Pid Controlled Sepic Converter Systems

DYNAMIC CONTROL OF INTERLEAVED BOOST CONVERTER FOR AUTOMOTIVE LED LIGHTING APPLICATION

Novel Passive Snubber Suitable for Three-Phase Single-Stage PFC Based on an Isolated Full-Bridge Boost Topology

A Novel Bidirectional DC-DC Converter with Battery Protection

The Design and Implementation Of Single Stage Zero Voltage Switching Converter With Boost Type Active Clamp

Push-Pull Quasi Resonant Converter Techniques used for Boost Power Factor Corrector

ISSN Vol.03,Issue.11, December-2015, Pages:

HIGH EFFICIENCY BRIDGELESS PWM CUK CONVERTER WITH SOFT SWITCHING TECHNIQUE

K.Vijaya Bhaskar. Dept of EEE, SVPCET. AP , India. S.P.Narasimha Prasad. Dept of EEE, SVPCET. AP , India.

A DC DC Boost Converter for Photovoltaic Application

Power Factor Improvement With High Efficiency Converters

A NOVEL SOFT-SWITCHING BUCK CONVERTER WITH COUPLED INDUCTOR

Key words: Bidirectional DC-DC converter, DC-DC power conversion,zero-voltage-switching.

Closed loop control of an Improved Dual switch Converter With Passive Lossless Clamping For High Step-Up Voltage Gain

Single Phase Single Stage Power Factor Correction Converter with Phase Shift PWM Technique

A Predictive Control Strategy for Power Factor Correction

Performance Enhancement of a Novel Interleaved Boost Converter by using a Soft-Switching Technique

International Journal of Engineering Research and General Science Volume 3, Issue 4, July-August, 2015 ISSN

CHAPTER 2 GENERAL STUDY OF INTEGRATED SINGLE-STAGE POWER FACTOR CORRECTION CONVERTERS

SIMPLIFICATION OF HORMONICS AND ENHANCEMENT OF POWERFACTOR BY USING BUCK PFC CONVERTER IN NON LINEAR LOADS

CHAPTER 3. SINGLE-STAGE PFC TOPOLOGY GENERALIZATION AND VARIATIONS

Bidirectional DC-DC Converter Using Resonant PWM Technique

DESIGN OF BRIDGELESS HIGH-POWER-FACTOR BUCK-CONVERTER OPERATING IN DISCONTINUOUS CAPACITOR VOLTAGE MODE.

A HIGHLY EFFICIENT ISOLATED DC-DC BOOST CONVERTER

A New Closed Loop AC-DC Pseudo boost Based Converter System for CFL

A Novel Concept in Integrating PFC and DC/DC Converters *

Phase Shift Modulation of a Single Dc Source Cascaded H-Bridge Multilevel Inverter for Capacitor Voltage Regulation with Equal Power Distribution

Modified Bridgeless Buck Rectifier with Single Inductor for Power Factor Correction

Comparison and Simulation of Full Bridge and LCL-T Buck DC-DC Converter Systems

Sepic Topology Based High Step-Up Step down Soft Switching Bidirectional DC-DC Converter for Energy Storage Applications

ACEEE Int. J. on Control System and Instrumentation, Vol. 02, No. 02, June 2011

This paper deals with a new family of high boostvoltage inverters, called switched-inductor quasi-z-source inverters.

MICROCONTROLLER BASED ISOLATED BOOST DC-DC CONVERTER

Simulation and Analysis of Zero Voltage Switching PWM Full Bridge Converter

A Switched Capacitor Based Active Z-Network Boost Converter

A High Efficient DC-DC Converter with Soft Switching for Stress Reduction

Transcription:

International Journal of Scientific & Engineering Research, Volume 4, Issue 4, April-2013 473 Flyback with Half Wave Rectifier for Single Stage Power Factor Correction K.Umamaheswari*, V.Venkatachalam ** * Research Scholar, Anna University, Chennai. ** Principal, The Kavery Engineering College, Mecheri. Abstract - The flyback converter type single-stage converter and a half wave rectifier with time-multiplexing control (TMC) for power factor correction is proposed. It has the advantage of better magnetic core utilization and better performance for high power applications. The major portion of the input is transferred to the load through ac-dc conversion. And the part of the input power is delivered to the auxiliary output through the flyback conversion and stored in the capacitor. The voltage ripple of the main output can also be reduced. With TMC the power processes can be achieved by single transformer to reduce the cost and the size of the converter. The simulation result of the proposed converter presents, simplicity, high power factor with low cost and size. Index Terms -Power Factor Correction (PFC), Single Stage, Flyback Converter. 1. INTRODUCTION During the past two decades, power electronics research has focused on the development of new families of hard- and soft-switching converter topologies used in the design of dc dc and ac dc converters with active power factor corrections (PFC s). The goal is to design highefficiency and high-power density converters with improved power factor and low electromagnetic interference (EMI). In recent years, as the new standards such as IEC 1000-3-2 became compulsory regarding limiting the total harmonic distortion (THD) and input power factor in power electronic circuits, researchers are actively seeking ways to shape the line current waveform to achieve THD and power factor that comply with international standards. Active PFC circuits that use pulse width modulation (PWM) switch-mode topologies such as the boost, buck boost, and their derived ones have been used dominantly. The steady-state analyses for a large number of such topologies are well documented, and their various dc control characteristics are well known. In addition to the steady-state behavior, the dynamic behavior is equally important and critical when it comes to the design of a robust control system for such converters. Control theory is applied to improve the performance of power electronics circuits such as the transient response, control accuracy, regulation capability and to reduce the effects of parameter variations as well as other disturbances. Over the last two decades, several control schemes have been presenting various modeling techniques for the power stage. A novel one-switch one-stage converter is proposed in, which features universal line voltage operation, near unity power factor, high efficiency, and low THD in the input current. With the increasing demand for power from the ac line and more stringent limits for power quality, power factor correction has gained great attention in recent years Power Factor Correction (PFC) technique continues to be attractive research topic with several effective regulations being reported. Conventional cascade of two stage topology can achieve good performance such as high power factor and low voltage stress, but it usually suffers from high cost and increased circuit complexity. Many single-stage PFC AC/DC converters have been proposed that can be applied cost-effectively. However, it s well known that in single stage topologies, the voltage across the bulk capacitor can not be controlled well due to the fact that only one switch and control loop are used. Moreover, the storage capacitor voltage varies widely with the input voltage and load variation, especially when the PFC operates in DCM mode while DC/DC stage operates in CCM mode. Finally, the storage capacitor voltage will increase to be unbearable under light load condition. Fig.1 Power Factor Triangle (Lagging) Power Factor Correction (PFC) converter is necessary for many electronic types of equipment to meet harmonic regulations and standards, such as IEC 1000-3-2. For low power applications, single-stage PFC converter is a better choice considering cost and performance. In single switch topologies, a PFC cell is integrated with a DC/DC

International Journal of Scientific & Engineering Research, Volume 4, Issue 4, April-2013 474 conversion cell and both cells share active switches and controller. But those topologies suffer from high voltage and high current stresses. But most of those methods will bring high distortion to line current waveform, resulting in reduced power factor. In recent years the power factor correction problem is solved by single-stage flyback converter with time multiplexing control [1]. In order to improve the power factor, several single stage PFC circuits have been developed. Flyback and forward converters are the common topologies for active PFC [2], [5],[15],[16].These converters allow the input current to be shaped into a rectified sine wave, which is in phase with the input voltage, achieving the high power factor. Resonant power factor correction circuits have been introduced which are named as full-bridge and half-bridge [17], [18]. Soft switching technique has also been used in these converters [7], [8], [13], [17]. The single stage soft switching regulators are attractive because of its soft commutation and low voltage stress. Single-stage parallel PFC schemes or direct power transfer (DPT) technique is also used. Fig.2. There are several disadvantages of the twostage PFC converter, for example, the total efficiency of the two-stage is lower because the total power has to be processed twice with two cascade power stages and each power stage has to be rated as full output power which will increase the size and cost of the circuits. output to the main output by applying the time multiplexing control (TMC). TMC has been introduced in telecommunication systems. The channel divides into N time slots and transmits each signal through the assigned time slot. This solves the problem when the resource is limited. This paper applies TMC technique to controlling the auxiliary output. This output has its own feedback control circuit to control switch to regulate the output voltage and to minimize the output ripple. PFC converter proposed in consists of a single forward converter operating in discontinuous conduction mode (DCM). In order to reduce the low frequency output voltage ripple, an auxiliary circuit with a bulk capacitor is used to produce an anti-phase voltage ripple to the line frequency ripple. However, there is no isolation between the bulk capacitor and the output. The high bulk capacitor voltage would cause safety issues. 2. TOPOLOGY AND OPERATION PRINCIPLE Fig. 3 shows the topology of the proposed single-stage PFC circuit based on a forward AD/DC converter. The circuit consists of a forward converter with an auxiliary circuit with a transformer T1, a reset winding L3, a capacitor Caux, a diode D3, and a switch S2. With the control of S1, the major power is directly transferred through the forward part to the load. The output voltage is represented by Vmain. Some energy is transferred to the auxiliary circuit, stored in Caux. With the control of S2, the power is transferred from auxiliary flyback part to the main output. Low output line-frequency voltage ripple is obtained by controlling the power from the auxiliary circuit through the duty cycle of S2.The signal of switches S1 and S2 are shown in Fig, 3. With the TMC control, switch S1 operates during t0-t1 period while S2 operates during t2-t3 period. The operation of current can be divided into five stages. Fig. 2 Two-stage Power-Factor-Corrected (PFC) Converter approach The proposed converter in this paper consists of a forward converter integrated with an auxiliary flyback converter. The major input power is delivered directly to the load through the forward converter avoiding double power processing while excessive energy is stored in the capacitor of the auxiliary flyback converter. The overall efficiency of the system can be improved by maximizing the power processed by the forward converter. The linefrequency voltage ripple of the main output is minimized by controlling the energy transferred from the auxiliary Fig. 3 Flyback converter and half wave rectifier

International Journal of Scientific & Engineering Research, Volume 4, Issue 4, April-2013 475 inductance. This keeps input current to flow into the circuit, preventing any dead angle of input current to occur. The load at main output is supplied by the capacitor Cmain. a) Stage I (b) Stage II Stage II The switch turns off and switch S2 is off in this stage. The energy previously stored in the magnetic field is delivered to the main output through flyback conversion. At the same time, the free-wheeling diode in the auxiliary out is on. Stage III The switch S2 turns on and switch S1 is off in this stage. The auxiliary output capacitor stores energy in the transformer through the auxiliary winding. The load at main output is supplied by the capacitor Cmain. Stage IV The switch S2 turns off and switch S1 is off in this stage. The energy is thus transferred from the auxiliary output to the main output through the flyback conversion in Stage III. The main output voltage can be well regulated by controlling the turn-on time of the switch S2. 3. CIRCUIT ANANLYSIS AND DESIGN CONSIDERATION (c) Stage III a) Conventional two stage PFC (d) Stage IV Fig.4 Equivalent circuit of each stage Stage I The switch S1 turns on and switch S2 is off in this stage. The supply voltage Vin charges the primary inductance. Meanwhile, the supply voltage transfers power to the auxiliary output through forward conversion when Vin is larger than the reflected voltage from the auxiliary voltage Vaux. Otherwise, the transformer acts solely as a coupled inductor, storing energy through the primary b) Proposed single-stage PFC scheme Fig. 5 Power transfer diagrams

International Journal of Scientific & Engineering Research, Volume 4, Issue 4, April-2013 476 For not only the two-stage PFC converter scheme but also the single-stage PFC converter shown in Fig. 5, the input power had to transferred twice before producing to the load. The input power is firstly transferred to store in the bulk capacitor though the PFC AC/DC stage. Then, it is transferred to the load through the DC/DC stage. These result that the overall efficiency is reduced due to the double power transferred. The proposed PFC converter applies direct power transfer (DPT) to increase the overall power conversion efficiency. Part of the input power P1 is directly transferred to the output, rest of the power P2 is delivered to the auxiliary output and stored in the bulk capacitor with some losses. Efficiency For both the conventional two-stage PFC scheme and the single-stage PFC scheme sharing one power switch, the input power have been processed twice before applying to the load, the input power is first transferred through PFC functional stage to store in intermediate bulk capacitor. The stored power is then transferred through dc dc functional stage to the load. Double power processing results in low overall efficiency of those schemes. (a) With 220V input voltage P =η1. k.pin P2 =η2.(1- k).pin P3 =η. P2 Pout =P1 + P 2 (b) Input current where = efficiency of the flyback ac-dc stage(p1) 2 = efficiency of the half wave rectifier ac-dc stage (P2) 3 = efficiency of the flyback ac-dc stage(p3) k= percentage of input power directly transferred to the load The proposed single-stage PFC scheme uses DPT idea to achieve high overall efficiency. The part of the input power P1 is directly transferred to the output and rest of input the power P2 is delivered to the auxiliary output and stored in the intermediate bulk capacitor (auxiliary). Eventually, the stored power P3 will be transferred to the main output through flyback dc dc conversion with TMC. (c) Input pulse to the switches This topology has been simplified with fewer components to save cost.the auxiliary output voltage is still naturally clamped within the range.the bulk capacitor (auxiliary)is charged directly when the switch S1 turns on; it results in high initial input current i1 which is reflected from the auxiliary output current i3.

International Journal of Scientific & Engineering Research, Volume 4, Issue 4, April-2013 477 obtained according to maximize the percentage of DPT. Only a single transformer is used for all the power conversion. The simulation results confirm the effectiveness of the proposed scheme for the proposed Single-Stage PFC converter. (d) Waveform of line voltage and line current (e) Output DC voltage waveform Fig.6 waveforms of input voltage, line current, output voltage and input pulses The input voltage Vin and input current Iine are shown in Fig.6. It indicates that high power factor has been obtained with the proposed PFC converter by applying the different input voltages. The input current is nearly perfect sine wave. The reason causing this result is when Vin is larger than the Vmain, the major input power transfer to the output through the forward conversion; when Vin is smaller than the Vmain, the circuit is worked as a flyback converter. This avoids the dead-angle appeared, increases the power factor compared to a classical forward converter. The third harmonic in the input is largely caused by the zero-crossing distortion.thd is 3.91% when upto 40 th harmonic are measured. The zero-crossing distortion energy is spread among multiple frequencies at 5 th, 7 th, 9 th and 11 th harmonics, such that THD is actually lower than that under 60Hz input. 4. CONCLUSION The replacement of forward converter by the half wave rectifier gives the cost efficiency and high power factor. A forward-based Single-Stage PFC converter with TMC based on direct power transfer (DPT) concept is proposed in this paper. High power factor is achieved which is shown in the simulation result. Successful control of TMC of the auxiliary power switch results in lower output voltage ripple and tight voltage regulation. High efficiency is REFERENCES [1] Flyback-Based Single-Stage Power-Factor-Correction Scheme With Time-Multiplexing Control Jun Zhang, Dylan Dah-Chuan Lu, Senior Member, IEEE, and Ting Sun-IEEE transaction vol-57,no:3,march-2010. [2] M.A.Dalla Costa, J.M.Alonso, J.C.Miranda, and D.G.Lamar, A single-stage high-power-factor electronic ballast based on integrated buck flyback converter to supply metal halide lamps, IEEE Trans.Ind.Electron.,vol.55,no.3,pp.1112 1122,Mar.2008. [3] M.G.Egan, D.L.O Sullivan, J.G.Hayes, M.J.Willers, and C.P.Henze, Power-factor-corrected single-stage inductive charger for electric vehicle batteries, IEEE Trans. Ind. Electron.,vol.54,no.2, pp.1217 1226,Apr.2007. [4] G.Moschopoulos and P.Jain, Single-phase single-stage power-factor Corrected converter topologies, IEEE Trans. Ind. Electron., vol.52, no.1, pp.23 35,Feb.2005. [5] H.F.Liu and L.K.Chang, Flexible and low cost design for a flyback AC/DC converter with harmonic current correction, IEEE Trans.Power Electron., vol.20, no.1, pp.17 24, Jan.2005. [6] J.M.Kwon, W.Y.Choi, and B.H.Kwon, Single-switch quasi-resonant converter, IEEE Trans. Ind. Electron., vol.56, no.4, pp.1158 1163, Apr.2009. [7] E.Adib and H.Farzanehfard, Family of zero-current transition PWM converters, IEEE Trans.Ind. Electron., vol.55, no.8, pp.3055 3063, Aug.2008. [8] Y.M.Liu and L.K.Chang, Single-stage soft-switching AC DC converter with input current shaping for universal line applications, IEEE Trans. and.electron., vol.56, no.2, pp.467 479, Feb.2009. [9] L.Antonio, B.Andrs, S.Marina, S.Vicente, and O.Emilio, New power factor correction AC DC converter with reduced storage capacitor voltage, IEEE Trans. Ind.Electron.,vol.54, no.1, pp.384 397,Feb.2007. [10] R. Redl, L. Balogh, and N. O. Sokal, A new family of single-stage isolated power-factor correctors with fast regulation of the output voltage, in Proc. 25th Annu EEE PESC, Jun. 1994, vol. 2, pp. 1137 1144. [11] C. M. Wang, A novel single-switch single-stage electronic ballast with high input power factor, IEEE Trans. Power Electron., vol. 22, no. 3, pp. 797 803, May 2007. [12] M. Ponce, A. J. Martinez, J. Correa, M. Cotorogea, and J. Arau, Highefficient integrated electronic ballast for

International Journal of Scientific & Engineering Research, Volume 4, Issue 4, April-2013 478 compact fluorescent lamps, IEEE Trans. Power Electron., vol. 21, no. 2, pp. 532 542, Mar. 2006. [13] C. S.Moo, K. H. Lee, H. L. Cheng, and W.M. Chen, A single-stage high power-factor electronic ballast with ZVS buck-boost conversion, IEEE Trans. Ind. Electron., vol. 56, no. 4, pp. 1136 1146, Apr. 2009. [14] J. Y. Lee and M. J. Youn, A single-stage power-factorcorrection converter with simple link voltage suppressing circuit (LVSC), IEEE Trans. Ind. Electron., vol. 48, no. 3, pp. 572 584, Jun. 2001. [15] J.J.Lee, J. M. Kwon, E. H. Kim, W. Y. Choi, and B. H. Kwon, Single stage single-switch PFC flyback converter using a synchronous rectifier, IEEE Trans. Ind Electron., vol. 55, no. 3, pp. 1352 1365, Mar. 2008. [16] K.Feel-Soon, P. Sung-Jun, and U. K. Cheul, ZVZCS single- stage PFC AC-to-DC half-bridge converter, IEEE Trans. Ind. Electron., vol. 49,no. 1, pp. 206 216, Feb. 2002. [17] S. Kyoung - Wook and K. Bong-Hwan, A novel singlestage half- bridge AC DC converter with high power factor, IEEE Trans. Ind. Electron.,vol. 48, no. 6, pp1219 1225, Dec. 2001. [18] D. Dai, S. N. Li, X. K. Ma, and C. K. Tse. "Slow-Scale Instability of Single-Stage Power-Factor-Correction Power Supplies." IEEE Trans. On Circuits and Systems I: Regular Papers, vol.54, pp.1724-1735, Aug 2007. [19] B. R. Lin, C. L. Huang, and M. Y. Li. "Novel zero voltage switching dual-switch forward converter with ripple current cancellation." Electric Power Applications, IET, vol.1, pp.799-807, Sep 2007. [20] R. T. Chen and Y. Y. Chen, Single-stage push pull boost converter with integrated magnetics and input current shaping technique, IEEE Trans.Power Electron., vol. 21, no. 5, pp. 1193 1203, Sep. 2006. [21] A. Fernandez, J. Sebastian, F. F. Linera, and A. Ferreres, Single-stage AC-to-DC converter with self-driven synchronous rectification that complies with EN61000-3-2 regulations, IEEE Trans. Ind. Electron., vol. 50,no. 5, pp. 1062 1064, Oct. 2003. [22] J. A. Villarejo, J. Sebastian, F. Soto, and E. de Jodar, Optimizing the design of single-stage power-factor correctors, IEEE Trans. Ind. Electron.,vol. 54, no. 3, pp. 1472 1482, Jun. 2007. [23] J. Y. Lee, Single-stage AC/DC converter with inputcurrent dead-zone control for wide input voltage ranges, IEEE Trans. Ind. Electron., vol. 54, no. 2, pp. 724 732, Apr. 2007. [24] A. K. S. Bhat and R. Venkatraman, A soft-switched full-bridge singlestage AC-to-DC converter with lowline-current harmonic distortion, IEEE Trans. Ind. Electron., vol. 52, no. 4, pp. 1109 1116, Aug. 2005..