Hybrid Energy Transfer Power Factor Correction AC/DC Converters With Improved Efficiency

电力电子技术广泛应用于各种工业部门，最近被科学技术政策办公室确定为美国经济未来增长的关键。今天，电子产品的创新正以前所未有的速度发展。然而，电力电子技术并没有跟上中低档电力电子工业的发展步伐。通过该提案，pi寻求通过探索新的设计技术来提高电源性能，以开发一系列高效，高频，低功率和中功率的AC-DC转换器，降低成本和提高可靠性，并且仍然实现接近统一的功率因数。这项工作的目标是下一代计算机和通信系统中使用的高速微处理器未来严格的功率要求。提出的研究目标是开发新型混合能量传输AC-DC转换器，提高效率和可靠性，并提供功率因数校正（PFC）。在传统的单级AC/DC-PFC方案中，变换器通常工作在不连续传导模式（DCM），具有简单、低成本和高可靠性的优点，但由于其固有的高电压和电流应力，效率不高。此外，它不能同时实现低功率因数和谐波方面的预期输入性能，以及电压纹波和调节能力方面的输出性能。两级方案可以实现统一的功率因数和更高的输出性能，但代价是元件数高，系统复杂性增加。这反过来又增加了成本，降低了整个电力电子系统的可靠性。在单级和两级AC/DC转换器中，功率被处理两次，因为所有传输的能量将一次存储在中间散装电容器中。在这里，我们提出了一种新的方法，允许能量传输的并行路径，以减少功率处理时间，提高转换器的效率和可靠性。大部分输入功率直接转移到输出，而不经过输入电流整形阶段，而转换器保持接近统一的功率因数。此外，考虑到两个级联变换器中PFC级和DC-DC级的操作无关性，pi还提出了一种新的概念，通过将PFC级与DC-DC级连接起来，在不添加任何辅助开关的情况下为PFC级或DC/DC级提供软开关条件，以提高效率。在项目为期两年的时间内，将进行以下主要任务：1)调查现有PFC- AC/DC变换器提高效率的局限性。2)以减少功率损耗和处理时间为目标，分析潮流特征，构建将部分输入功率直接转发到输出端的势能路径，使功率处理时间最小化。3)比较现有的实用软开关DC/DC拓扑结构；在PFC级和DC/DC级之间开发合适的磁耦合路径，以相互受益，例如为PFC级或/和DC/DC级提供软开关条件。4)研究综合系统问题和可能的解决方案，重点研究不同阶段和控制方案之间的相互作用。5)搭建仿真平台和物理试验台，对所提出的拓扑结构与现有AC/DC变换器的整体性能进行比较研究。

Power electronics technology is widely used in various industrial sectors and has recently beenidentified by the Office of Science and Technology Policy as critical for the future growth of the U.S.economy. Today innovations in electronic products are progressing at an unprecedented rapid pace.However, power electronics technology has not kept pace with the growth in low and medium powerelectronic industries. With this proposal, the PIs seek to improve the power supply performance byexploring new design techniques to develop a family of efficient, high-frequency, low and mediumpower AC-DC converters with reduced cost and improved reliability, and still achieve near unitypower factor. This effort targets future stringent power requirements for high-speed microprocessorused in next generation computer and communication systems.The objective of the proposed research is to develop novel hybrid energy transfer AC-DC convertersimproved efficiency and increased reliability and provides Power Factor Correction (PFC). In atraditional single-stage AC/DC-PFC scheme, the converter normally operates in DiscontinuousConduction Mode (DCM) and has the advantages of simplicity, low cost and high reliability, whileless efficiency due to its inherent high voltage and current stresses. Moreover, it cannot achievesimultaneously, the desired input performance in terms of low power factor and harmonics, andoutput performance in terms of voltage ripple and regulation capabilities. The two-stage scheme canachieve unity power factor and higher output performance, but at the expense of high componentcount and increased system complexity. This in turn increases cost and degrades the reliability of thewhole power electronic system. In both single-stage and two-stage AC/DC converters, the power isprocessed twice as all the transferred energy would once store in an intermediate bulk capacitor. Here,we propose a novel method that allows parallel path of energy transfer to minimize power-processingtimes and to improve converter efficiency and reliability. A lion share of the input power directlytransferred to the output without going through the input current shaping stage while the converterremains a near-unity power factor. Furthermore, considering the operation irrelevance of PFC stageand DC-DC stage in two cascade stage converters, the PIs also propose a novel concept to improvethe efficiency by linking PFC stage with DC-DC stage to provide soft-switching conditions for thePFC stage or DC/DC stage without adding any auxiliary switch.During the projects two-year period, the following major tasks will be carried out:1) Investigate the limitations of improving efficiency in existing PFC- AC/DC converters.2) Aiming at reducing the power losses and processing time, analyze the power flow features,and build the potential path to forward partial input power to the output side directly tominimize the power processing times.3) Compare existing practical soft-switching DC/DC topologies; develop the suitable magneticcoupling paths between the PFC stage and DC/DC stage to benefit each other, such asproviding soft-switching condition for PFC stage or/and DC/DC stage.4) Investigate integrated system issues and possible solutions, focusing on interaction betweendifferent stages and control schemes.5) Set-up simulation platform and physical test bed, conduct comparative study for overallperformance between the proposed topology and existing AC/DC converters.