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

Western Michigan University, Kalamazoo MI

Investigators

Abstract

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 students 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.