This timely second edition has been substantially expanded to keep students and practicing power conversion engineers ahead of the learning curve in GaN technology advancements. Acknowledging that GaN transistors are not one-to-one replacements for the current MOSFET technology, this book serves as a practical guide for understanding basic GaN transistor construction, characteristics, and applications. Included are discussions on the fundamental physics of these power semiconductors, layout and other circuit design considerations, as well as specific application examples demonstrating design techniques when employing GaN devices.

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GaN Transistors for Efficient Power Conversion

The dual-active-bridge (DAB) topology is ideally suited for high-power dc-dc conversion, especially when bidirectional power transfer is required. However, it has the drawback of high circulating currents and hard switching at light loads, if wide variation in input and output is expected. To address these issues, this paper presents a comprehensive analysis and experimental results with pulsewidth-modulation (PWM) control of the DAB. The PWM control is in addition to phase-shift modulation between the two H-bridges. The analysis addresses PWM of one bridge at a time and of both bridges simultaneously. In the latter, five distinct modes arise based on the choice of PWM and load condition. The possibilities are analyzed for optimizing power density and efficiency for low-load operation. Finally, a composite scheme combining single and dual PWM is proposed that extends the soft-switching range down to zero-load condition, reduces rms and peak currents, and results in significant size reduction of the transformer. Experimental results are presented with a 10-kW prototype.

Pwm control of dual active bridge: Comprehensive analysis and experimental verification

Inductive power transfer (IPT) and capacitive power transfer (CPT) are the two most pervasive methods of wireless power transfer (WPT). IPT is the most common and is applicable to many power levels and gap distances. Conversely, CPT is only applicable for power transfer applications with inherently small gap distances due to constraints on the developed voltage. Despite limitations on gap distance, CPT has been shown to be viable in kilowatt power level applications. This paper provides a critical comparison of IPT and CPT for small gap applications, wherein the theoretical and empirical limitations of each approach are established. A survey of empirical WPT data across diverse applications in the last decade using IPT and CPT technology graphically compares the two approaches in power level, gap distance, operational frequency, and efficiency, among other aspects. The coupler volumetric power density constrained to small gap sizes is analytically established through theoretical physical limitations of IPT and CPT. Finally, guidelines for selecting IPT or CPT in small gap systems are presented.

A Survey of Wireless Power Transfer and a Critical Comparison of Inductive and Capacitive Coupling for Small Gap Applications

In this paper, an interleaved active-power-filter concept with reduced size of passive components is discussed. The topology is composed of two pulsewidth-modulation interleaved voltage-source inverters connected together on the ac line and sharing the same dc-link capacitor. The advantages of the proposed approach are as follows: 1. significant reduction in the linkage inductors' size by decreasing the line-current ripple due to the interleaving; 2. reduction of the switching stress in the dc-link capacitor, due to the shared connection; and 3. more accurate compensation for high-power applications, because the power sharing allows one to use a higher switching frequency in each inverter. This paper analyzes the design of the passive components and gives a practical and low-cost solution for the minimization of the circulation currents between the inverters, by using common-mode coils. Several simulation results are discussed, and experimental results with a three-phase 10-kVA 400-V unit are obtained to validate the theoretical analysis.

Shunt Active-Power-Filter Topology Based on Parallel Interleaved Inverters

Higher order LCL filters are essential in meeting the interconnection standard requirement for grid-connected voltage source converters. LCL filters offer better harmonic attenuation and better efficiency at a smaller size when compared to the traditional L filters. The focus of this paper is to analyze the LCL filter design procedure from the point of view of power loss and efficiency. The IEEE 1547-2008 specifications for high-frequency current ripple are used as a major constraint early in the design to ensure that all subsequent optimizations are still compliant with the standards. Power loss in each individual filter component is calculated on a per-phase basis. The total inductance per unit of the LCL filter is varied, and LCL parameter values which give the highest efficiency while simultaneously meeting the stringent standard requirements are identified. The power loss and harmonic output spectrum of the grid-connected LCL filter is experimentally verified, and measurements confirm the predicted trends.

Filter Optimization for Grid Interactive Voltage Source Inverters

Fundamentals of Magnetics. Magnetic Materials and Their Characteristics. Magnetic Cores, Iron Alloy and Ferrites. Window Utilization and Magnet Wire. Transformer-Inductor Design. Transformer-Inductor Efficiency, Regulation, and Temperature Rise. Power Transformer Design. DC Inductor Design Gap Core. DC Inductor Design Powder Core. AC Inductor Design. Constant Voltage Transformer Design (CVT). Three Phase Transformer Design. Flyback Converter Design. Forward Converter Transformer and Inductor Design. Input Filter Design. Current Transformer Design. Winding Capacitance and Leakage Inductance. Quiet Converter Design. Rotary Transformer Design. Planar Transformers. Derivation for the Design Equations. Index.

Transformer and inductor design handbook

Magnetic-core power-handling ability transformer output circuits transformer and inductor design examples magnetic-core material trade-off conversion data for magnet wire cased toroids MPP and iron powder cores ferrite cores laminations C cores caseless toroids E cores PC board mounts/headers and transformer mounting brackets.

Magnetic core selection for transformers and inductors : a user's guide to practice and specification

Transformer and inductor design philosophy magnetic materials magnetic cores window utilization, magnetic wire and insulation coil winding layer foil and toroidal soldering and magnet wire termination packaging, enclosures, mounts and headers polymeric impregnates, embedment and adhesives high voltage design guidelines testing, evaluation and quality assurance.

Colonel William T. McLyman

Papers

Transformer and inductor design handbook

Magnetic core selection for transformers and inductors : a user's guide to practice and specification

High Reliability Magnetic Devices: Design & Fabrication