Front-end converter design and system integration techniques in distributed power systems

Power conversion system design issues are becoming increasingly important in state-of-the-art electronic systems, especially in computing and information system applications. These issues include not only improving power conversion efficiency, but also increased concerns regarding the cost and complexity of the power converters and systems utilized to satisfy the host system's total performance requirements. Further, system integration techniques, which can be used in “building blocks” to implement a wide range of power electronic circuits and systems, will be taking a critical role to innovate conventional designs and also bring profound effects into practical applications.; This dissertation explores front-end converter design and system integration techniques in distributed power systems (DPS), with the objective of achieving improvements in converter topology, system performance, system configuration and cost-effectiveness over conventional approaches. Key issues of single-stage (S2) power-factor-correction (PFC) converters are addressed and the solutions to these issues are investigated. An optimization design procedure of a family of S2 converters, which is based on the averaging circuit model and MathCAD tool, is developed and verified by both simulation and experiment. A new PFC cell is presented with the direct-power-transfer (DPT) concept, and a new family of S2 converters is derived and experimentally verified, which has excellent characteristics that help push S2 converters into medium power applications. A comparison study of high power down converters is conducted, and in particular, experimental comparison of high power level for secondary-side topologies is completed in this dissertation, which demonstrates that the current doubler rectification topology is a viable choice for high-efficiency converters. The dissertation also investigates system level techniques such as interleaving, paralleling and configuration simplification. New interleaving method for high power converters is presented and simulated results demonstrate its potentials in decreasing filter size and increasing power density. New paralleling methods for power converters have been obtained based on the comprehensive classification and evaluation of paralleling approaches of power supply modules. The dissertation also describes the operation principle, design considerations, and experimental results of an AC-DPS with multiple PWM-wave buses. Finally, a redundant AC-DPS with trapezoidal waveform bus is proposed.