This article looks at the operation of the sepic and compares the design procedure for two single winding inductors with a coupled inductor approach. The design operates over an input voltage range of 7 v to 45 v and offers minimal voltage ringing on the fet for lower stress and reduced emi. Sepic mode converters for automotive lcd displays technical. The complete model derivation of the sepic converter system has been presented in different modes of operation. The technique is simple and elegant and does not require complicated mathematical computation. Designing dcdc converters based on sepic topology introduction the singleended primaryinductance converter sepic is a dcdcconverter topology that provides a positive regulated output voltage from an input voltage that varies from above to below the output voltage. Comparative analysis of performance of the sepic converter. The discontinuous conduction mode sepic and cuk power factor. Modified sepic converter has known by its advantage for lower voltage stresses. Figure 2 and figure 3 show the sepic converter current flow and switching waveforms. Each circuit occupies a component area of just over three square inches.
Mar 31, 2017 sepic converter design singleended primaryinductor converter sepic is a type of dcdc converter which can be step up the voltage or step down the voltage by changing duty cycle of the switch. The sepic converter dc analysis is presented, showing why this is a popular converter. The analysis and design work is present in this article for a nonisolated hard switching dcm sepic pfc. Steady state and small signal analysis was carried out on the converter dynamic equations using the method of harmonic balance technique. This study discusses the design of a paralleloperated dcdc singleended primaryinductor converter sepic for lowvoltage application and current sharing with a constant output voltage. A sepic singleended primary inductance converter is distinguished by.
Home design center modeling s01 sepic full analysis s01 sepic full analysis the complete analysis of the sepic converter the only place where this can be found. The sepic converter can both step up and step down the input voltage, while maintaining the same polarity and the same ground reference for the input and output. Controller design for sepic converter using model order reduction asar international conference, bangalore chapter 20, isbn. In addition, a pi controller is employed in converter circuit. An1484designing a sepic converter texas instruments. Parasitic resistances are included in the pspice model. Simulation with the sepic topology sepicsingle ended. Hardware design of sepic converter and its analysis. The singleended primaryinductor converter sepic is a type of dcdc converter which allows voltage at its output to be greater than, less than, or equal to than at its input voltage. The lt8580 can be configured as either a boost, sepic or inverting converter. Figure 1 shows the basic sepic converter with a coupled inductor. This article looks at each approach and discusses the impact each has on a practical sepic converter design. Ssa technique 1 state space modeling is a technique that describes a given system using a system of linear differential equations. Before reading this section, please read the introduction to dc to dc converter design.
Circuit operation figure 1 shows the basic sepic converter with a coupled inductor. Sepic equations and component ratings tutorial maxim. Experiment 8 design and experimentation of a sepic converter. Despite the lack of documentation for the converter, engineers continue to use it when applicable. Pdf modeling and analysis of dcdc sepic converter with. The sepic converter allows a range of dc voltage to be adjusted to maintain a constant voltage output. Analysis and design of a new extendable sepic converter with. Florencki a thesis submitted in partial fulfillment of the requirements for the degree of master of science electrical engineering at the university of wisconsinmadison 20. The steadystate analysis and the design of the converter are discussed thoroughly. With the sepic converter, the input inductor, l1, slows down the input current edges thus providing a lower noise buck regulator solution. The mcp1661 highvoltage boost and sepic converters evaluation board was developed to help engineers reduce product design cycle time. Abstract in a single ended primary inductance converter sepic design, the output voltage can be higher or lower than the input voltage.
Inductor selection for sepic designs electronic products. Design and analysis of a buckboost converter circuit for piezoelectric energy harvesting system abstract. Highpower cccv battery charger using an inverse sepic zeta. The two inductors can be wound on the same core since the same voltages are applied to them throughout the switching cycle. Design and analysis of high gain modified sepic converter. Singleended primaryinductor converter sepic is a switching regulator topology that allows the output voltage to be lower, equal or higher than the input voltage. Due to dcm operation of speic converter, wide adjustable stepdown output voltage, continuous conduction of input current and elimination of reverse recovery loss can be achieved at same time. Notice that if you visually rotate the sepic converter around the y axis, it looks almost exactly like the inverse sepic converter below with the additionsubtraction of an. An intuitive explanation of the sepic topology and some information on the history of its development by prof. Psim software has been used for simulation purpose and the total.
Benefits of a coupledinductor sepic converter ee times. Sepic equations and component ratings tutorial 1051 sepic equations and component ratings apr 23, 2002 lithium batteries, powerfactor converters, and improved lowesr capacitors are giving a new shine to the classic sepic topology. Sepic mode converters for automotive lcd displays technical overview video. Pmp9512 reference design sepic converter delivers 3. Design and analysis of a high frequency resonant sepic bidirectional converter and the associated battery modeling for battery equalization applictations by timothy j. Figures 3 and 4 show the demo circuit schematics for the prototype hardware in figure 1. The paper presents modeling approach of a single ended primary inductance converter sepic system. The conventional buck converter has sharp edges on the input current that can interfere with circuitry connected to the input voltage. A novel technique using a sepic converter to efficiently boost the input voltage to the system has been presented. In this paper qualitative analysis and controller design of a ti sepic converter for optimal utilization photovoltaic power is presented. When the fet q1 turns on, the input voltage is applied across the primary winding. Flyback and sepic converter design equations l is assumed to be large. Modeling, simulation and performance analysis of sepic converter.
The singleended primaryinductor converter sepic is a type of dcdc converter that allows the electrical potential at its output to be greater than, less than, or equal to that at its input. This figure shows a specific design example for a 15 w converter. The pfc and dcdc sepic converter circuits are illustrated in figure 2. Control of tisepic converter for optimal utilization of pv. The paper presents a unified steadystate analysis of pwm sepic converter with coupled inductors and separate inductors for both continuous and discontinuous conduction modes. Design of paralleloperated sepic converters using coupled. Prof, electrical and electronics engineering, nigama engineering college telangana india abstract. Experiment 8 design and experimentation of a sepic converter for led lighting 8. Analysis of the sepic converter computer action team. How do designers get away with building such a convertfigure 7. A coupled inductor is used for parallelconnected sepic topology. In order to analyze the operation of the sepic pfc converter, numerical simulations were performed in software for both the nominal condition. Pmp21883 fouroutput, sepic converterbias power supply. The results of this simplified analysis allow to determine the operating point of converters and further the smallsignal lowfrequency.
Analysis and design of a dcm sepic pfc with adjustable output. The lt8580 has an adjustable oscillator, set by a resistor from the rt pin to ground. Two high static gain stepup dcdc converters based on the modified sepic converter are presented in this project. Analysis and design of a new extendable sepic converter with high voltage. The zeta converter power train is depicted in figure 1. The power stage of closed loop system is a nonlinear system. The lt8580 is a pwm dcdc converter containing an internal 1a, 65v switch. The sepic converter definitely has some select applications where it is the topology of choice. The output of the sepic is controlled by the duty cycle of the control. All of the circuits in this tutorial can be simulated in ltspice. Sepic vs flyback the choice between a flyback or singleended primary inductance converter sepic topology often ends with the designer choosing the most familiar one, but thats not always the right option, say john betten and robert kollman. The derived dynamic model enables insight into the physical properties of the converter and gives relations between converter parameters and dynamic properties of the system. Designing dc dc converters based on sepic topology introduction the singleended primaryinductance converter sepic is a dc dcconverter topology that provides a positive regulated output voltage from an input voltage that varies from above to below the output voltage. The purpose of this project was to design and optimize a sepic dcdc converter single.
The equivalent circuit can be used directly in digital software simulators spice. The schematic below shows a working design, with the boosting voltage provided by the upper secondary of the transformer. Ac analysis of the sepic converter you wont find a complete analysis of the sepic converter anywhere in printed literature. The output voltage is controlled by duty cycle of the control transistor. The sepic converter made simple and how did it evolve. Calculation of output voltage ripple and design considerations of sepic converter. Sep 22, 2016 learn the basics of a dcdc sepic converter, its advantages compared to other dcdc topologies, and how a sepic can help you in your automotive display design. However, zeta and buck transsfer equations are not the same, so compensation might have to change.
It also has the same buckboost md d1d conversion ratio as the sepic converter. As with the sepic converter, there are two switching cycles that are presented in figure 2. Adaptive and nonlinear control techniques applied to sepic. Mcp1661 highvoltage boost and sepic converters evaluation board. Matlabsimulink software has been used to simulate sepic converter. M1, mohd abdul nadeem2 1 student, electrical and electronics engineering nigama engineering college telangana india 2 asst. Experimental results are provided by a 220w prototype. Design and analysis of a buckboost converter circuit for. This paper suggests a converter design that will ensure high performance and cost. In the last article, we talked about the simplest of all converters, the buck converter, and showed how its control transfer functions could be extraordinarily complex. Performance analysis of integrated sepic flyback converter for power factor correction drive applications krishnaveni. It has become popular in recent years in batterypowered systems which must step up or down depending upon the charge level of the battery.
Analysis and design domingos savio lyrio simonetti. Coupled inductors can simplify your sepic circuit design. Therefore it is a good starting point in converter design oriented analysis. The sepic converter shown in figure 1 uses two inductors. The output of the sepic is controlled by the duty cycle of the control switch s1. Therefore, this comparative analysis of performance of the sepic converter using pid and fuzzy logic controllers for led lighting applications b. The purpose of this project was to design and optimize a sepic dcdc converter single ended primary inductance converter. This converter is essentially combination of conventional buck and sepic converters sharing common components. What you will find are application notes with comments like, the sepic is not wellunderstood. This type of conversion is handy when the designer uses voltages e. Pdf calculation of output voltage ripple and design. The paper focuses on modeling sepic converter in ccm continuous conduction mode mode. Apr 02, 2017 the above video gives an abstract view of the working of the open loop sepic. During q1 offtime 2 an1484designing a sepic converter snva168e may 2006 revised april 20 submit documentation feedback.
Sepic converter is derived by the method of circuit averaging and averaged switch modelling 6. Modeling, steadystate analysis of a sepic dcdc converter. Sepic converter, this design also does not invert the input to output polarity. In addition, matlab simulink model is designed to show how it can be used as a buck or boost converter. Bob explains how sepic converters work on the white board and then shows a real circuit using the lm3481 lowside nchannel controller. A oneswitch sepic converter can be driven with a boost converter chip, while a oneswitch zeta converter needs a buckstyle drive because its switch it in the positive rail top diag. This circuit is optimized for input voltages within 3. This characteristics can be obtained in a single ended primary inductor converter sepic. The zeta converter power train the two switches, q1 and q2, operate out of phase. The results verify the proper operation and feasibility.
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