Design Of High Frequency Zero Voltage Transition Pulse Width Modulated Dc Dc Converter
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Design Of High Frequency Zero Voltage Transition Pulse Width Modulated Dc Dc Converter
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Author : Boon Cheng Pek
language : en
Publisher:
Release Date : 1996
Design Of High Frequency Zero Voltage Transition Pulse Width Modulated Dc Dc Converter written by Boon Cheng Pek and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1996 with categories.
Variable Frequency Pulse Width Modulation For Zero Voltage Switching In A Boost Dc Dc Regulator
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Author : Daniel Scott Hunter
language : en
Publisher:
Release Date : 1990
Variable Frequency Pulse Width Modulation For Zero Voltage Switching In A Boost Dc Dc Regulator written by Daniel Scott Hunter and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1990 with Electric power distribution categories.
A technique for operating a pulse-width-modulated (PWM) dc-dc regulator in the boost mode while switching the MOSFET when the drain-to-source potential is near zero volts was developed and is described in this thesis. This is accomplished by using frequency-modulation in addition to pulse-width-modulation. Zero-voltage switching will provide power converter designers an alternative for designing high-frequency converters with minimal transient turn-on losses, the predominant form of converter losses experienced in high frequency operation. High frequency operation will result in smaller reactive components, which produce higher power density converters, as well as increasing the transient response of the regulated converter. In addition to allowing for high frequency operation, the design exhibits many desirable power switch properties, such as limiting the peak voltage to the output voltage level and operating with the minimum possible current levels for a given power requirement. A circuit built and tested utilizing zero-voltage switching in a regulated boost converter verified the principles of operation for yielding a high-efficiency, high-frequency converter. (RH).
Hard Switching And Soft Switching Two Switch Flyback Pwm Dc Dc Converters And Winding Loss Due To Harmonics In High Frequency Transformers
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Author : Dakshina S. Murthy Bellur
language : en
Publisher:
Release Date : 2010
Hard Switching And Soft Switching Two Switch Flyback Pwm Dc Dc Converters And Winding Loss Due To Harmonics In High Frequency Transformers written by Dakshina S. Murthy Bellur and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with DC-to-DC converters categories.
The flyback pulse-width modulated (PWM) DC-DC power converter is a very important circuit in switching mode power supply (SMPS) converters for low power applications. The main drawback of the conventional single-switch flyback converter is the high turn-off voltage stress suffered by the switch. The high voltage transients are caused by the resonant behavior of the transformer leakage inductance and the transistor output capacitance, resulting in ringing superimposed on the steady-state switch voltage level. This requires a transistor with higher voltage rating. However, a transistor with higher voltage rating has higher on-resistance causing higher conduction loss. The high voltage ringing also increases the switching loss. In addition, the switch voltage stress is not easily predictable because it is difficult to determine the magnitude of ringing during the design stage. The two-switch flyback DC-DC converter is an extended version of the single-switch flyback converter. The circuit arrangement with an addition of a power transistor and two clamping diodes to the conventional single-switch flyback converter leads to the two-switch flyback PWM DC-DC converter, which effectively reduces the switch overvoltage and eliminates the uncertainty of its value. The clamping diodes in the two-switch flyback converter clamps the voltage across each switch to the DC input voltage and also provide a path to return most of the energy stored in the transformer leakage inductance to the DC input source. In the first part of this research, detailed steady-state analyses of the two-switch flyback PWM DC-DC converter for continuous conduction mode (CCM) and discontinuous conduction mode (DCM) are performed. The transistor output capacitance and the transformer leakage inductance are included in the analyses. Design equations for both CCM and DCM operation modes are derived. Furthermore, by incorporating an active clamp circuit into the hard-switching two-switch flyback converter, a new soft-switching two-switch flyback converter, namely, zero-current transition (ZCT) two-switch flyback converter is proposed. The principle of circuit operation, steady-state analysis, equivalent circuits, converter steady-state waveforms, and design procedure of the proposed ZCT two-switch flyback converter is presented. The key features of the proposed soft-switching converter are 1) the voltage stresses of the main switches are reduced to DC input voltage VI, and 2) all the semiconductor devices are turned off under zero-current (ZC) switching condition. Clamping of the switch overvoltages and reduction in switching loss are achieved in the proposed ZCT two-switch flyback converter. Saber Sketch simulation and experimental results of the hard-switching and the proposed ZCT soft-switching two-switch flyback converters are presented to validate the theoretical analyses. High frequency (HF) transformers used in PWM converters, such as flyback transformers conduct periodic nonsinusoidal currents, which give rise to additional winding losses due to harmonics. In the second part of this research, a theory is developed to find the harmonic winding loss in an HF transformer conducting periodic nonsinusoidal current. Dowell's equation is used to determine the winding resistances due to eddy currents as a function of frequency. Both skin and proximity effects are taken into account. Fourier series of the primary and secondary current waveforms in a two-winding flyback transformer and the primary and secondary winding resistances are used to determine the primary and secondary winding power losses at various harmonics for both CCM and DCM cases, respectively. The harmonic winding loss factors FRph and FRsh are introduced. The theory is illustrated by the case study of flyback converter for both CCM and DCM operations. Using the equations developed to find the winding losses due to harmonics, detailed methodology and step-by-step procedures to design two-winding flyback transformers for CCM and DCM operations, respectively, are given. Examples illustrating the design of two-winding flyback transformer for CCM and DCM operations are presented. Computed characteristics of the designed flyback transformer for a wide range of operating conditions of the flyback converter in CCM and DCM modes are presented.
New Topologies And Modulation Schemes For Soft Switching Isolated Dc Dc Converters
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Author : Zhiqiang Guo
language : en
Publisher: Springer Nature
Release Date : 2019-09-20
New Topologies And Modulation Schemes For Soft Switching Isolated Dc Dc Converters written by Zhiqiang Guo and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-09-20 with Technology & Engineering categories.
This book presents a series of new topologies and modulation schemes for soft-switching in isolated DC–DC converters. Providing detailed analyses and design procedures for converters used in a broad range of applications, it offers a wealth of engineering insights for researchers and students in the field of power electronics, as well as stimulating new ideas for future research.
Soft Switching Dc Dc Converters
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Author : Ahmad Mousavi
language : en
Publisher:
Release Date : 2013
Soft Switching Dc Dc Converters written by Ahmad Mousavi and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with categories.
Power electronics converters are implemented with switching devices that turn on and off while power is being converted from one form to another. They operate with high switching frequencies to reduce the size of the converters' inductors, transformers and capacitors. Such high switching frequency operation, however, increases the amount of power that is lost due to switching losses and thus reduces power converter efficiency. Switching losses are caused by the overlap of switch voltage and switch current during a switching transition. If, however, either the voltage across or the current flowing through a switch is zero during a switching transition, then there is no overlap of switch voltage and switch current so in theory, there are no switching losses. Techniques that ensure that this happens are referred to as soft-switching techniques in the power electronics literature and there are two types: zero-voltage switching (ZVS) and zero-current switching (ZCS). For pulse-width modulated (PWM) Dc-Dc converters, both ZVS and ZCS are typically implemented with auxiliary circuits that help the main power switches operate with soft-switching. Although these auxiliary circuits do help improve the efficiency of the converters, they increase their cost. There is, therefore, motivation to try to make these auxiliary circuits as simple and as inexpensive as possible. Three new soft-switching Dc-Dc PWM converters are proposed in this thesis. For each converter, a very simple auxiliary circuit that consists of only a single active switching device and a few passive components is used to reduce the switching losses in the main power switches. The outstanding feature of each converter is the simplicity of its auxiliary circuit, which unlike most other previously proposed converters of similar type, avoids the use of multiple active auxiliary switches. In this thesis, the operation of each proposed converter is explained, analyzed, and the results of the analysis are used to develop a design procedure to select key component values. This design procedure is demonstrated with an example that was used in the implementation of an experimental prototype. The feasibility of each proposed converter is confirmed with experimental result obtained from a prototype converter.
Pulse Width Modulated Dc Dc Power Converters
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Author : Marian K. Kazimierczuk
language : en
Publisher: Wiley-Blackwell
Release Date : 2008-10-20
Pulse Width Modulated Dc Dc Power Converters written by Marian K. Kazimierczuk and has been published by Wiley-Blackwell this book supported file pdf, txt, epub, kindle and other format this book has been release on 2008-10-20 with Technology & Engineering categories.
This book starts by introducing semiconductor power devices, describing the characteristics of static and dynamicDC voltage regulators and power MOSFETs (metal-oxide semiconductor field effect transistors). It goes on to discuss transformerless converters, such as buck, boost, and buck-boost converters. Transformer converters, such as flyback, forward, half-bridge, full-bridge, and push-pull converters are also analysed, with summaries and design procedures. High-frequency inductors and transformers are considered in depth toward the end of the book, along with magnetics. Review questions a.
Auxiliary Circuit Assisted Soft Switching Techniques And Their Application To Power Converters
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Author : Ranganathan Gurunathan
language : en
Publisher:
Release Date : 1999
Auxiliary Circuit Assisted Soft Switching Techniques And Their Application To Power Converters written by Ranganathan Gurunathan and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1999 with categories.
The need to incorporate significant improvements in power supplies is driven by customer demands, industry requirements and regulatory standards. For reduction in size and weight, it is imperative to process the power at a higher switching frequency. High frequency processing of power requires soft switching techniques to reduce the switching losses. Many soft switching techniques are reported in the literature to enhance the high frequency operation of power supplies. This thesis proposes novel high frequency, auxiliary circuit assisted, (a) soft-switched boost converters and their application to DC-to- DC converters and AC-to-DC front-end power factor corrected converters; and (b) zero-voltage switching (ZVS) dc link DC-to-AC inverters. In auxiliary circuit assisted soft transition converters, the auxiliary circuit processes the power during switching transitions, creating a soft transition path. In most of the proposed converters in the literature, the auxiliary circuit suffers from severe switching losses and switching stress. Discontinuous current operation of the auxiliary circuit results in parasitic oscillations between the switch capacitance and the resonant inductors increasing the stress on the devices. A zero-current switching (ZCS) auxiliary circuit and ZVS auxiliary circuit are proposed in this thesis to achieve soft transitions for the main circuit. A ZCS auxiliary circuit assisted soft transition boost converter is proposed. Operating intervals of the proposed technique in various intervals of operation are analyzed. Design constraints and considerations are discussed. A 300 W dc-to-dc boost converter and a 600 W, ac-to-dc power factor correction front-end boost converter prototype models are built in the laboratory. The experimental results confirm the theory. The resonant inductor used in the auxiliary circuit is coupled weakly to the boost inductor. Although parasitic oscillations are reduced due to the coupling, they are not completely eliminated. Hence, RC snubbers are required to suppress the oscillations. A ZVS auxiliary circuit assisted soft transition boost converter is also presented. Operating intervals of the proposed converter in various intervals of operation are analyzed. As all the parasitic elements in the circuit are accounted, parasitic oscillations are eliminated. A 300 W dc-to-dc converter operating at 250 kHz is built in the laboratory to verify the theory. A modified gating scheme to utilize the soft switching auxiliary circuit in the main power processing is also proposed. A 600 W, 100 kHz, 380 V dc, operating with universal input line voltage, ac-to-dc power factor corrected (PFC) boost converter is built using the proposed technique with modified gating algorithm. Large signal analysis to analyze the soft switching characteristics of the proposed technique during load and input voltage transients is also presented. PSPICE simulation results are presented to verify the theory. The proposed converter maintains soft switching during load and input voltage transients. The proposed auxiliary network is also extended to a family of pulse width modulated (PWM) converters. A two-switch soft switching boost converter is derived from the proposed converter. By integrating the proposed auxiliary network with a full bridge inverter, a ZVS dc link voltage source inverter (VSI) is obtained. Operating intervals of the proposed inverter in various intervals of operation for the forward power flow and reverse power flow are presented. A modified unipolar switching scheme to achieve ZVS during reverse power flow is also presented. The voltage stress on the VSI is clamped to the dc bus voltage in the proposed converter. The conduction losses are reduced as compared to other soft switching converters in the literature. As the proposed technique requires synchronized PWM operation, sine-ramp modulated PWM signals are used. Experimental results from a 120 V, 60 Hz, 300 VA, single phase VSI switching at 50 kHz are presented to verify the theory.
Power Electronics Handbook
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Author : Muhammad H. Rashid
language : en
Publisher: Elsevier
Release Date : 2010-07-19
Power Electronics Handbook written by Muhammad H. Rashid and has been published by Elsevier this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010-07-19 with Technology & Engineering categories.
Power electronics, which is a rapidly growing area in terms of research and applications, uses modern electronics technology to convert electric power from one form to another, such as ac-dc, dc-dc, dc-ac, and ac-ac with a variable output magnitude and frequency. Power electronics has many applications in our every day life such as air-conditioners, electric cars, sub-way trains, motor drives, renewable energy sources and power supplies for computers. This book covers all aspects of switching devices, converter circuit topologies, control techniques, analytical methods and some examples of their applications. * 25% new content* Reorganized and revised into 8 sections comprising 43 chapters* Coverage of numerous applications, including uninterruptable power supplies and automotive electrical systems* New content in power generation and distribution, including solar power, fuel cells, wind turbines, and flexible transmission
Dc Dc Converter Topologies
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Author : Gerry Moschopoulos
language : en
Publisher: John Wiley & Sons
Release Date : 2024-01-31
Dc Dc Converter Topologies written by Gerry Moschopoulos and has been published by John Wiley & Sons this book supported file pdf, txt, epub, kindle and other format this book has been release on 2024-01-31 with Technology & Engineering categories.
A comprehensive look at DC-DC converters and advanced power converter topologies for all skills levels As it can be rare for source voltage to meet the requirements of a Direct Current (DC) load, DC-DC converters are essential to access service. DC-DC power converters employ power semiconductor devices (like MOSFETs and IGBTs) as switches and passive elements such as capacitors, inductors, and transformers to alter the voltage provided by a DC source into the necessary DC voltage as is required by a DC load. This source can be a battery, solar panels, fuel cells, or a DC bus voltage fed by rectified AC utility voltage. As the many components of DC-DC converters can be differently arranged into circuit structures called topologies, there are as many possible circuit topologies as there are possible combinations of circuit elements. Focusing on DC-DC switch-mode power converters ranging from 50 W to 10kW, DC-DC Converter Topologies provides a survey of all converter topology types within this power range. General principles are described for each topology type using a representative converter as an example. Variations that can be found that differ from the example are then examined, with a helpful discussion of comparisons when relevant. A broad range of topics is covered within the book, from simple, low-power converters to complex, high-power converters and everywhere in between. DC-DC Converter Topologies readers will also find: A detailed discussion of four key DC-DC converter topologies Description of isolated two-switch pulse-width modulated (PWM) topologies including push-pull, half-bridge, and interleaved converters An exploration of high-gain converters such as coupled inductors, voltage multipliers, and switched capacitor converters This book provides the tools so that a non-expert will be equipped to deal with the vast array of DC-DC converters that presently exist. As such, DC-DC Converter Topologies is a useful reference for electrical engineers, professors, and graduate students studying in the field.
Switch Mode Power Converters
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Author : Keng C. Wu
language : en
Publisher: Elsevier
Release Date : 2005-12-01
Switch Mode Power Converters written by Keng C. Wu and has been published by Elsevier this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005-12-01 with Technology & Engineering categories.
Switch-Mode Power Converters introduces an innovative, highly analytical approach to symbolic, closed-form solutions for switched-mode power converter circuits. This is a highly relevant topic to power electronics students and professionals who are involved in the design and analysis of electrical power converters. The author uses extensive equations to explain how solid-state switches convert electrical voltages from one level to another, so that electronic devices (e.g., audio speakers, CD players, DVD players, etc.) can use different voltages more effectively to perform their various functions. Most existing comparable books published as recently as 2002 do not discuss closed-loop operations, nor do they provide either DC closed-loop regulation equations or AC loop gain (stability) formulae. The author Wu, a leading engineer at Lockheed Martin, fills this gap and provides among the first descriptions of how error amplifiers are designed in conjunction with closed-loop bandwidth selection. BENEFIT TO THE READER: Readers will gain a mathematically rigorous introduction to numerous, closed-form solutions that are readily applicable to the design and development of various switch-mode power converters. Provides symbolic, closed-form solutions for DC and AC studies Provides techniques for expressing close-loop operation Gives readers the ability to perform closed-loop regulation and sensitivity studies Gives readers the ability to design error amplifiers with precision Employs the concept of the continuity of states in matrix form Gives accelerated time-domain, steady-state studies using Laplace transform Gives accelerated time-domain studies using state transition Extensive use of matrix, linear algebra, implicit functions, and Jacobian determinants Enables the determination of power stage gain that otherwise could not be obtained