Author: Kavya Suma Gompa Publisher: ISBN: Category : Languages : en Pages : 218
Book Description
The dual active bridge isolated dc-dc converter is the most widely chosen converter for high-power density bidirectional power flow applications with its inherent galvanic isolation and ease of realizing soft-switching capabilities[1]. Modern power electronics often have to sustain higher ranges of loads and especially for applications like Point of Load (POL) regulators and data-centre specific applications where the conversion ratio is very high and also the converter lives in light load conditions for a significant part of its lifetime. In such converters the light load efficiency improvements without effecting the full-load conditions, thereby improving the overall efficiency of the converter is critical. One key learning for a converter design is that it is crucial when learning about more advanced converter topologies to understand the science behind how it works and especially understanding the design trade-offs. The proposed converter architecture proposed in this thesis illustrates a 48-1.8V single conversion with an input-series-output-parallel (ISOP) architecture. The attractive features of the converter are (a) light load efficiency improvements without impacting the full-load efficiency, (b) single-switch resonant gating design for a full-bridge inverter (c) data driven design strategy for the converter topology
Author: Achim Seidel Publisher: Springer Nature ISBN: 3030689409 Category : Technology & Engineering Languages : en Pages : 137
Book Description
This book explores integrated gate drivers with emphasis on new gallium nitride (GaN) power transistors, which offer fast switching along with minimum switching losses. It serves as a comprehensive, all-in-one source for gate driver IC design, written in handbook style with systematic guidelines. The authors cover the full range from fundamentals to implementation details including topics like power stages, various kinds of gate drivers (resonant, non-resonant, current-source, voltage-source), gate drive schemes, driver supply, gate loop, gate driver power efficiency and comparison silicon versus GaN transistors. Solutions are presented on the system and circuit level for highly integrated gate drivers. Coverage includes miniaturization by higher integration of subfunctions onto the IC (buffer capacitors), as well as more efficient switching by a multi-level approach, which also improves robustness in case of extremely fast switching transitions. The discussion also includes a concept for robust operation in the highly relevant case that the gate driver is placed in distance to the power transistor. All results are widely applicable to achieve highly compact, energy efficient, and cost-effective power electronics solutions.
Author: John K. George Publisher: ISBN: Category : Languages : en Pages : 348
Book Description
A symmetrical LLC resonant converter topology with a fixed-frequency quasi-triple phase-shift modulation method is proposed for battery-powered electric traction systems with extensions to other battery storage systems. Operation of the converter with these methods yields two unique transfer characteristics and is dependent on the switching frequency. The converter exhibits several desirable features: 1) load-independent buck-boost voltage conversion when operated at the low-impedance resonant frequency, allowing for dc-link voltage regulation, zero-voltage switching across a wide load range, and intrinsic load transient resilience; 2) power flow control when operated outside the low-impedance resonance for integrated battery charging; 3) and simple operational mode selection based on needed functionality with only a single control variable per mode. Derivation of the transfer characteristics for three operation cases using exponential Fourier series coefficients is presented. Pre-design evaluation of the S-LLC converter is presented using these analytical methods and corroborated through simulation. Furthermore, the construction of a rapid-prototyping magnetics design tool developed for high-frequency transformer designs inclusive of leakage inductance, which is leveraged to create the magnetic elements needed for this work. Two 2kW prototypes of the proposed topology are constructed to validate the analysis, with one prototype having a transformer incorporating the series resonant inductance and secondary clamp inductance into the transformer leakage and magnetizing inductance, respectively. A test bench is presented to validate the analysis methods and proposed multi-operational control scheme. Theoretical and experimental results are compared, thus demonstrating the feasibility of the new multi-mode operation scheme of the S-LLC converter topology.
Author: Hengsi Qin Publisher: ISBN: Category : Electric current converters Languages : en Pages : 202
Book Description
"This dissertation presents a comprehensive study of Dual Active Bridge (DAB) converters for Solid State Transformers (SSTs). The first contribution is to propose an ac-ac DAB converter as a single stage SST. The proposed converter topology consists of two active H-bridges and one high-frequency transformer. Output voltage can be regulated when input voltage changes by phase shift modulation. Power is transferred from the leading bridge to the lagging bridge. It analyzes the steady-state operation and the range of zero-voltage switching. It develops a switch commutation scheme for the ac-ac DAB converters. Simulation and experiment results of a scaled down prototype are provided to verify the theoretical analysis. The second contribution is to develop a full-order continuous-time average model for dc-dc DAB converters. The transformer current in DAB converter is purely ac, making continuous-time modeling difficult. Instead, the proposed approach uses the dc terms and 1st order terms of transformer current and capacitor voltage as state variables. Singular perturbation analysis is performed to find the sufficient conditions to separate the dynamics of transformer current and capacitor voltage. Experimental results confirm that the proposed model predicts the small-signal frequency response more accurately. The third contribution addresses the controller design of a dc-dc DAB converter when driving a single-phase dc-ac inverter. It studies the effect of 120 Hz current generated by the single-phase inverter. The limitation of PI-controller is investigated. Two methods are proposed to reduce the voltage ripple at the output voltage of DAB converter. The first method helps the feedback loop with feedforward from inverter, while the second one adds an additional resonance controller to the feedback loop. Theoretical analysis, simulation and experiment results are provided to verify the effectiveness of the proposed methods"--Abstract, leaf iii.
Author: Brian Sargent Publisher: ISBN: 9781471807213 Category : Juvenile Nonfiction Languages : en Pages : 440
Book Description
Endorsed by Cambridge Assessment International Education Now including Brian Sargent in the expert author team, alongside first edition authors Graham Brown and David Watson, this book has been fully revised and updated to cover every part of the latest Cambridge IGCSE ICT (0417) syllabus. - Written by experts, who bring a wealth of theoretical knowledge and practical experience to both the book and the CD - Ensures that students are fully prepared for both the written theory paper as well as the two practical papers - Covers each section of the syllabus with clear explanations and plenty of tasks and activities Every Student's Book includes a CD that contains source files for the tasks and activities. Answers to all questions can be found on the Teacher's CD Rom.
Author: Kavya Suma Gompa
Author: Deniz Yıldırım (Danışman.)
Author: Achim Seidel
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Author: John K. George
Author: Hengsi Qin
Author: Brian Sargent
Author: Roger Harrison