Modelling and Design Optimisation of a High Bandwidth and High Precision Optical Current Sensor Based on the Faraday Effect

A magneto-optical current measurement system based on the Faraday effect is evaluated for measuring fast pulse currents in high power applications. The current measurement system is based on the interaction of the magnetic field, generated by the current, and a beam of light propagating through magneto-optical material which is in close proximity to the current conductor. A high local magnetic field per ampère current inside the optical path is required to improve the accuracy and the sensitivity of the optical current measurement sensor.In this paper, the relation between the conductor geometry and the local magnetic field distribution is analytically modelled resulting in the geometry factor Kg. The analytical model enables an optimisation of the busbar geometry to increase the overall probe sensitivity and the accuracy of the optical current measurement system