ERI: Multiphysics cosimulation approach for optimal design of microgrid high frequency transformers

微电网是能够脱离公用事业电网运行的电力网络，它们是正在进行的能源革命的关键参与者。微电网领域现有知识的进步对于通过提高美国电网的可靠性同时减少其碳足迹来改变目前的能源格局至关重要。微电网的特点是广泛包含可再生能源和分布式能源，使用智能技术，并为现代电力系统的弹性和能效做出贡献。微电网的广泛应用面临的一个重要挑战是它们在运行过程中承受着巨大的电磁和热应力，因此迫切需要设计出新型、更高效、更具弹性的微电网元件。电力电子变流器尤其如此，它被广泛用于微电网与主电网的互联，以及发电源、储能系统和电力负载的接口。固态变压器是一种新型的电力转换器，由于其体积、重量和成本都大大减少，因此与传统电力变压器相比效率高、占地面积小；它们还包括智能功能，可以更好地应对电网扰动。因此，由于可再生资源的广泛增加，固态变压器具有取代传统变压器的潜力。从固态变压器的主要部件中，高频变压器被认为是其关键元件。高效且经济实惠的高频变压器设计对于实现固态变压器的主要要求至关重要：高密度、最小损耗、电压调节和电气隔离。到目前为止，由于可靠性和运行寿命的考虑，这种设计一直是固态变压器在配电系统和微电网中主流采用的瓶颈。在这个项目中，我们建议使用新颖和创新的建模和仿真工具来优化设计高频变压器，以最大化其运行寿命，并在微电网应用的条件下将故障或损坏的可能性降至最低。该项目的主要目标是评估新型多物理和微电网建模和仿真工具的协同组合对微电网应用的高频变压器优化设计的有效性，考虑到在稳态和暂态条件下广泛包含电力电子接口源、负载和存储单元所产生的压力。为了实现这一目标，该项目包括开发、实施和全面测试一种建模方法，以准确地动态模拟微电网系统及其与详细的基于物理的高频变压器模型的在线交互。考虑到微电网运行的特殊挑战，提出的联合仿真方法是对现有设计工具的实质性改进。通过采用多物理和多目标设计方法，本项目旨在获得增强型高频变压器设计，最大限度地提高设备的效率、运行寿命和功率密度。通过将有限元分析和动态系统仿真工具相结合，该项目旨在将这两种工具的优势结合起来，作为增强设计优化过程的一个组成部分：在各种正常和非正常运行条件下进行准确、逼真的微电网仿真，以及高频变压器的详细几何和材料多物理模型。拟议项目的成功完成将是在微电网和配电系统中广泛使用SST的重要一步，这反过来又可以大大提高可再生发电的整合效率以及向用户输送电力的效率。除了这个项目的科学目标外，PI还努力利用这个项目作为一个平台，改善工程教育，并招募不同背景的人来动力工程。为了推动这些成果，PI将开展夏季本科生研究计划，为学生提供相关电力工程和电磁设计领域的真正研究经验和培训。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Microgrids are electrical networks capable of operating disconnected from the utility grid, and they are key players in the ongoing energy revolution. Advancement of the current knowledge in the field of microgrids is critical to transform the present energy landscape by increasing the reliability of the US electric power grid while reducing its carbon footprint. Microgrids are characterized by their extensive inclusion of renewable and distributed energy resources, use of smart technologies, and contribution to the resilience and energy-efficiency of modern power systems. An important challenge for the widespread implementation of microgrids is that they endure significant electromagnetic and thermal stresses during their operation, thus there is an urgent need for the design of novel, more efficient, and more resilient microgrid components. This is particularly true for power electronic converters, which are extensively used for microgrid interconnection to the main grid, and for interfacing of generation sources, energy storage systems and electric loads. Solid-state transformers are a novel type of power converter that has attracted a lot of attention because they are highly efficient and have a smaller footprint than conventional power transformers given their substantially reduced size, weight and cost; they also include smart functionalities to respond better to grid disturbances. Therefore, solid-state transformers have the potential of replacing traditional transformers for the widespread addition of renewable resources. From the main components of a solid-state transformer, the high frequency transformer is recognized as its key element. The efficient and affordable design of high frequency transformers is critical for achieving the main requirements of solid-state transformers: high density, minimal losses, voltage regulation, and electric isolation. Thus far such design has been a bottleneck for the mainstream adoption of solid-state transformers in distribution systems and microgrids due to reliability and operating life concerns. In this project, we propose the use of novel and innovative modeling and simulation tools for the optimal design of high frequency transformers to maximize their operating life and minimize the possibility of failure or damage under the conditions imposed by microgrid application. The outcomes of this project are expected to have a positive impact on the development of a more resilient and sustainable electrical power grid.The main goal of this project is to assess the effectiveness of the synergistic combination of novel multiphysics and microgrid modeling and simulation tools for the optimal design of high frequency transformers for microgrid application, considering the stresses produced by the extensive inclusion of power electronic-interfaced sources, loads, and storage units during steady state and transient conditions. To reach this goal, this project includes the development, implementation, and comprehensive testing of a modeling approach for accurate dynamic simulation of the microgrid system and its online interaction with a detailed physics-based high frequency transformer model. The proposed cosimulation approach constitutes a substantial improvement over existing design tools, considering the particular challenges of microgrid operation. By taking a multiphysics and multi-objective design approach, this project intends to obtain an enhanced high frequency transformer design that maximizes efficiency, operating life and power density of the device. By interfacing finite element analysis and dynamic system simulation tools, this project aims to combine the benefits from both tools as an integral part of an enhanced design optimization process: accurate and realistic microgrid simulation under a variety of normal and abnormal operating conditions, and detailed geometrical and material multiphysics modeling of the HF transformer. The successful completion of the proposed project will constitute an important step forward in the widespread utilization of SSTs in microgrids and distribution systems, which in turn can result in a significantly enhanced efficiency in the integration of renewable generation, as well as in the delivery of electricity to consumers. In addition to the scientific goals of this project, the PI endeavors to use this project as a platform for improving engineering education and recruiting individuals from diverse backgrounds to power engineering. In order to advance these outcomes, the PI will run a summer undergraduate research program to provide students with genuine research experiences and training in the interrelated power engineering and electromagnetic design areas.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.