Advancing impedance metrology in an extended frequency range

The Energy Efficiency and Renewable Energy directives aim to improve energy usage in Europe. Vital to this is an accurate measurement of electrical impedance - the opposition that an electrical circuit presents to the flow of alternating current. Impedance measurements are also important in a range of other areas including electronics manufacturing, energy storage and material characterisation. Modern advances, such as power electronics for renewable energy integration, or capacitors and inductors employed in switching converters, now require impedance measurements up to 2 MHz. However, the uncertainties of most commercial meters extend only into the low kHz range and require extrapolation for higher frequencies. These instruments are also generally protected by IP, making it challenging to evaluate their performance. Although advances in digital impedance bridges and Quantum Hall Resistance (QHR) standards could extend impedance measurements, these still require metrological development before use.

Building on AIM QuTE, GIQS, VersICal and QuAHME, this project will optimise new and existing impedance bridge methods to validate measurement uncertainties across a wide range of frequencies (100 mHz to 2 MHz). Developed techniques will allow the accurate calibration of commercial instruments, including impedance meters, analysers, and spectroscopy systems over this range, and graphene-based Quantum Hall devices will be investigated to outline a pathway towards a universal quantum impedance standard.

This will help manufacturers to better adhere to European directives in this area, improve the integration of renewable energies into the electricity gid, and allow advances in battery storage, material science, telecommunications and many more.