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

微电网是能够脱离公用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。通过提高美国电网的可靠性，同时减少其碳足迹，微电网领域当前知识的进步对于改变当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，并有助于现代电力系统的弹性和能源效率。微电网在运行过程中承受着显著的电磁和热应力，因此迫切需要设计出新颖、更高效、更有弹性的微电网组件，这是微电网广泛实施的一个重要挑战。电力电子变流器尤其如此，它广泛用于微电网与主电网的互连，以及发电源、储能系统和电力负荷的接口。固态变压器是一种新型的电源转换器，因为它们效率高，占地面积比传统的电力变压器小，因此引起了很多关注，因为它们的尺寸，重量和成本大大减少；它们还包括智能功能，可以更好地应对电网干扰。因此，固态变压器具有取代传统变压器的潜力，可广泛补充可再生资源。从固态变压器的主要部件来看，高频变压器是固态变压器的关键部件。高效、经济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，由于可靠性和使用寿命问题，这种设计一直是配电系统和微电网中固态变压器主流采用的瓶颈。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高频变压器的设计，以最大限度地延长其工作寿命，并最大限度地减少微电网应用条件下故障或损坏的可能性。预计该项目的成果将对建设更具弹性和可持续性的电网产生积极影响。该项目的主要目标是评估新型多物理场和微电网建模和仿真工具的协同组合的有效性，以优化微电网应用的高频变压器设计，考虑到在稳态和瞬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应力。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，用于对微电网系统进行精确的动态仿真，并与一个详细的基于物理的高频变压器模型进行在线交互。考虑到微电网运行的特殊挑战，所提出的联合模拟方法构成了对现有设计工具的实质性改进。通过采用多物理场和多目标设计方法，本项目旨在获得增强的高频变压器设计，最大限度地提高设备的效率，工作寿命和功率密度。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：在各种正常和异常运行条件下精确和逼真的微电网仿真，以及高频变压器的详细几何和材料多物理场建模。拟议项目的成功完成将是在微电网和配电系统中广泛利用sst方面向前迈出的重要一步，这反过来又可以大大提高可再生能源发电的整合效率，以及向消费者供电的效率。除了这个项目的科学目标，PI努力利用这个项目作为一个平台，以改善工程教育和招募来自不同背景的个人从事电力工程。为了推进这些成果，PI将运行一个夏季本科生研究项目，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。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.