Zero dynamics-based design of damping networks for switching converters

A new design technique of the input filter damping network for dc-to-dc switching converters of buck type is presented. This technique is derived by means of zero dynamics analysis of the switching converter and yields equivalent results to those obtained using the classical approach based on minimizing the filter output impedance. The new method can be applied in converters of buck type with two inductors, boost with two inductors and dual SEPIC. Simulation and experimental results corresponding to a boost converter with two inductors illustrate the procedure.     

Computer-Aided Design and Graphics Applied to the Study of Inductor-Energy -Storage Dc-to-Dc Electronic Power Converters

A series of nine programs are developed for the design of the inductors of single-winding flyback converters. Three converter types are considered: voltage step-up, current step-up, and voltage step-up/current step-up. For each of the converter types, three pulse modulators are considered: constant frequency, constant transistor on-time, and constant transistor off-time. Computer-graphics displays are used to assist in evaluating characteristics of the various converter-modulator combinations.     

Table-Aided Design of the Energy-Storage Reactor in DC-to-DC Converters

A new procedure for the selection of magnetic cores for use in energy-storage dc-to-dc power converters that eliminates the need for an automated computer search algorithm and stored data file is presented. The converter configurations included in the procedure are the three commonly encountered single-winding converters for voltage stepup, for current stepup and voltage stepup/current stepup, and for the two-winding converter for voltage stepup/current stepup. For each converter configuration, three types of controllers are considered: constant-frequency, constant on-time, and constant off-time. Using concepts developed from analyses of these converters by considering the transfer of energy by means of an energystorage inductor or transformer, a special table of parameters calculated from magnetic core data is constructed, which leads to a considerably simplified design procedure.     

Generation and classification of PWM DC-to-DC converters

A method is presented by which generation and classification of pulsewidth-modulated (PWM) DC-to-DC converters can be effected. Fundamental blocks known as converter cells can be used to generate a plethora of converters leading to a number of useful new converter topologies. A classification of basic converters is proposed in terms of converter-cell generated families     

A Large-Signal Dynamic Simulation for the Series Resonant Converter

A simple nonlinear discrete-time dynamic model for the series resonant dc-dc converter is derived using approximations appropriate to most power converters. This model is useful for the dynamic simulation of a series resonant converter using only a desktop calculator. The model is compared with a laboratory converter for a large transient event.     

Single-stage ZVS PWM full-bridge converter

A new soft-switched ac-dc single-stage pulse width modulation (PWM) full-bridge converter is proposed. The converter operates with zero-voltage switching (ZVS), fixed switching frequency, and with a continuous input current that is sinusoidal and in phase with the input voltage. This is in contrast with other ac-dc single-stage PWM full-bridge converters that are either resonant converters operating with variable switching frequency control and high conduction losses, converters whose switches cannot operate with ZVS, or converters that cannot perform power factor correction (PFC) unless the input current is discontinuous. All converter switches operate with soft-switching due to a simple auxiliary circuit that is used for only a small fraction of the switching cycle. The operation of the converter is explained and analyzed, guidelines for the design of the converter are given, and its feasibility is shown with results obtained from an experimental prototype.     

A Pulsewidth-Modulated Dc-to-Dc Converter That Utilizes a Small Number of Components

In general, circuit reliability can be enhanced by either incorporating redundancy or by minimizing a circuits component count. Conventional nonregulating converters generally require two active devices, whereas in regulating converters or switching regulators as many as 10 transistors, either integrated or discrete, is not uncommon. A regulating dc-to-dc converter which provides useful regulation and which can be constructed with either two or three transistors is described.     

General rules for signal flow graph modeling and analysis of dc-dc converters

Signal flow graph (SFG) nonlinear modeling approach is well known for modeling dc-dc converters. However, all possible SFGs of a given dc-dc converter system will not yield the generalized graph. A systematic procedure and guidelines for developing unified flow graph models of the dc-dc boost converters, from which complete behavior can be determined is presented. Usefulness of the proposed method is demonstrated through examples. As an illustration a 2-cell cascade boost and interleaved boost converter systems are taken as examples. Derivation of large, small-signal and steady-state models from generalized flow graph is also demonstrated. Large-signal model is developed and programmed in TUTSIM simulator. Large-signal, responses against supply and load disturbances are obtained. Experimental observations are provided to validate the proposed algorithm.     

Effect of FET output capacitance on ZVS of resonant converters

The analysis of resonant converters including the capacitance of the switches is presented. New dc characteristics are obtained for the series, parallel, and series-parallel resonant converters (SPRC). The operating regions where the converters operate with zero-voltage switching (ZVS) are determined as a function of the switch capacitance. The more pronounced effect can be seen in the series resonant converter (SRC), while the parallel resonant converter (PRC) is the most insensitive. The results of the analysis have been verified on an experimental prototype     

Generalized approach for μ synthesis of robust switchingregulators

A general method using μ synthesis to design controllers applicable to pulsewidth modulated (PWM) converters is described. System uncertainties from component tolerances are included in the synthesis procedure, adding a quantifiable measure of robustness. Furthermore, these uncertainties have been implemented in a structured format which maximizes available system performance. A boost converter example is presented demonstrating the controller synthesis procedure and advantages of this method     

Optimization of the Energy-Storage Inductors for DC-to-DC Converters

Three sets of design graphs and equations are developed to facilitate design of the energy-storage inductors for dc-to-dc converters. Using the design graphs, a quick estimate of the inductor minimum weight, the transistor peak current, and the inductor power loss can be obtained. Tradeoff studies can be conveniently conducted using these graphs. The effects of duty cycle controllers, constant frequency and constant tON, on the optimal selection of the energystorage inductors are assessed.     

Analysis of a parallel resonant converter with secondary-sideresonance

A high-frequency (HF) link parallel resonant DC/DC converter operating in the lagging power factor mode with the resonating capacitor on the secondary side of the HF transformer is analyzed using a state-space approach. Closed-form solutions (except for the duration of diode conduction) are obtained for steady-state conditions, and design curves are obtained. A method of obtaining optimum operating point under certain constraints is developed and is used as the basis of a simple design procedure. A theoretical study comparing the performance of three MOSFET-based 1-kW converters with different transformer turn ratios under load changes from rated-load to 10% load is carried out. Experimental results obtained with these converters with different transformer turn ratios are also presented     

Interleaved boost converter with zero diode reverse-recovery loss

A three-phase interleaved continuous-inductor-current-mode (CICM) boost converter with zero diode reverse-recovery loss is proposed. In the converter, the di/dt of the output rectifiers is controlled by an integrated magnetic component. All the output rectifiers can be turned off softly and a very high efficiency is obtained. The equivalent-circuit model of the integrated inductors, the operation principle of the converter, and the design issues are discussed. Simulation and experimental results are presented.     

CIECA: Application to Current Programmed Switching Dc-Dc Converters

Sundstrand Advanced Technology Corporation The current injection equivalent circuit approach (CIECA) to modeling switching converter power stages is extended to model the current programmed converter power stages operating in fixed frequency, continuous inductor conduction mode. To demonstrate the method, modeling is carried out for the buck, boost, and buckboost converters to obtain small-signal linear equivalent circuit models which represent both input and output properties. The results of these analyses are presented in the form of linear equivalent circuit models as well as transfer functions. Though current programmed converters exhibit single-pole response, the addition of artificial ramp changes converters to exhibit well damped two-pole response. This has been investigated for the first time using CIECA. The results of these analyses are presented in the form of linear equivalent circuit models as well as transfer functions.     

Two-phase forward converter using an integrated magnetic component

An interleaved two-phase forward converter using an integrated magnetic component is proposed for telecommunication and computer applications. The integrated magnetic component consists of two step-down transformers and two output-filtering inductors on a single magnetic core. The z-parameter (gyrator) model and the equivalent-circuit model of the integrated magnetic component are presented. The circuit operation and design criteria of the proposed converter are described. All theoretical analyses are verified by simulated and experimental results.     

Unified approach to developing single-stage power converters

A unified approach to developing single-stage power converters which can fulfil multiple functions is presented. Four synchronous switches corresponding to the four common node types of two active switches are introduced. The approach is then to replace the active switches in multistage converters (in cascade or cascode connection) with one or several of the synchronous switches and their degenerated versions to form a single-stage converter. Illustrations of using these switches to develop single-stage converters are presented. These are started with the development of the well-known single-stage switch-mode converters (SMCs), buck-boost, Cuk, sepic, and Zeta (also named dual sepic), from the basic converters, buck and boost. Then, synthesis and applications of other single-stage converters are addressed. Due to increased component stresses, the developed single-stage converters are primarily suitable for applications with moderate power levels     

Computer Simulations of Optimum Boost and Buck-Boost Converters

The development of mathematical models suitable for minimum weight boost and buck-boost converter designs are presented. The facility of an augumented Lagrangian (ALAG) multiplier-based nonlinear programming technique is demonstrated for minimum weight design optimizations of boost and buck-boost power converters. ALAG-based computer simulation results for those two minimum weight designs are discussed. Certain important features of ALAG are presented in the framework of a comprehensive design example for boost and buck-boost power converter design optimization. The study provides refreshing design insight of power converters and presents such information as weight and loss profiles of various semiconductor components and magnetics as a function of the switching frequency.     

Series of radiation-hardened, high efficiency converters for high voltage bus

A review of common switching techniques for dc/dc power conversion is presented. The evolution of the forward converter is discussed, leading naturally to the introduction of the double forward converter. Technical details for a series of radiation-hardened converters are then provided. This series was designed for space power management and distribution (PMAD) applications. The successful development of the PMAD converter demonstrated the viability of high voltage bus.     

Analysis and Design of Series Resonant Converter by State-Plane Diagram

Analysis based on the state-plane diagram is given for series resonant converters operating in the frequency range 0.5 ? fs/fo ? 1.0. When the voltages and currents in the converter are normalized, design parameters take on special geometric meanings in the normalized state diagram. Examples of converter design using graphical methods are given for the cases of ? and ? control. Control characteristics of the converter operating in the continuous conduction mode are derived. The concept of the energy reflection coefficient is introduced as a measure of power transfer efficiency in the converter design.     

Resonant power supplies: their history and status

The various types of converter are described, and the history of resonant power supplies is briefly sketched. The differences between pulse-width-modulated (PWM) switch mode power supplies and resonant power supplies are discussed. Single-switch, multiple-switch, and series and parallel resonant converters are examined. The control of resonant converters is addressed. Hardware is briefly considered