CAREER: Adjustable-Voltage-Ratio Magnetoelectric Transformer: A New Voltage Conversion and Control Device for Smart Grids

University Of Nebraska-Lincoln, Lincoln NE

Investigators

Abstract

Voltage conversion (i.e., converting voltage from one level to another) and control (i.e., regulating voltage within a certain range around the nominal value) is an important issue for the secure, economic operation of modern power grids, particularly future smart power grids with significant penetration of renewable energy resources. In current power grids, on-load tap-changing (OLTC) electromagnetic transformers, and step-voltage regulators have been commonly used for voltage conversion and control. However, the tap-changing mechanisms used in OLTC transformers and step-voltage regulators are typically a mechanical mechanism or an electromechanical mechanism with a slow response and can only adjust the voltage ratio of the transformer or regulator in discrete steps. Therefore, OLTC transformers and step-voltage regulators cannot meet the requirement for flexible, continuous, and fast-acting voltage conversion or control for future smart power grids. The current alternative is the solid-state transformer (SST). However, SSTs are currently still limited by voltage and power ratings of the solid-state devices and available circuit topologies. Moreover, when compared to traditional electromagnetic transformers, SSTs would require more complicated and expensive thermal management and may have a shorter life expectancy. This Faculty Early Career Development Program (CAREER) project will explore and prove a novel concept for a magnetoelectric transformer with a continuous and quickly adjustable voltage ratio for flexible, fast-acting voltage conversion and control to help secure the electricity supply, accommodate more renewable energy integration, and reduce the cost of electricity delivery. In addition, the project team will build a thriving, diversified electric power and energy program through the integration of graduate and undergraduate research and teaching with K-12 outreach. The program will provide a unique platform for training a new generation of young professionals to accommodate the changing environment and meet the emerging workforce and educational needs of the U.S. power and energy industry. The research goal of this project is to develop a complete framework for designing, prototyping, modeling, controlling, operating, and demonstrating a novel adjustable-voltage-ratio (AVR) magnetoelectric transformer for flexible, continuous, and fast-acting voltage conversion and control of power grids. The new capabilities of the proposed concept will be achieved through the development of: (1) a new voltage-controlled magnetoelectric device with an adjustable permeability to control the magnetic flux in the transformer, (2) a new transformer configuration for the integration of the flux control devices, and (3) new models and methods for controlling the voltage ratio of the transformer by regulating the magnetic flux using the new flux control devices in the transformer. This project will provide an innovative and transformative solution for overcoming the existing limitations of existing voltage conversion and control devices used in power grids. The physical and operating principles to be established and the models and design framework to be created for the new AVR transformer will build a solid theoretical foundation for future development and application of the proposed concept in power grids. Once the proposed concept is proven by this project, further development and deployment of the concept will require new advancements in different disciplines, such as electrical engineering, material science and engineering, system and control engineering, and mechanical engineering, thus stimulating the creation of new interdisciplinary research. The findings of this project will impact the control and operation of the future power grids, and will contribute to the creation of a smart power grid to provide better electric energy security, efficiency, and sustainability.