ELECTRO-OPTIC CURRENT SENSOR WITH HIGH DYNAMIC RANGE AND ACCURACY

摘要

An optical sensor that senses current by directing polarized light across an airgap that is orthogonal to a direction of current running through a conductor. The sensor includes a prism having a high Verdet constant for high sensitivity to magnetic fields, which cause an angle of polarization of the polarized light to be rotated as an indication of the magnitude of current. A polarizing beamsplitter having a low Verdet constant is mounted to the prism so that incoming light that is traveling in a direction orthogonal to the magnetic field being sensed across the airgap is insensitive to unwanted magnetic fields produced by nearby conductors. The distance the light travels in this orthogonal direction is minimized, reducing the overall volume of the sensor, making a compact sensor highly sensitive to magnetic fields of interest, largely insensitive to unwanted magnetic fields, and having a very high dynamic range for sensing current.

主权项

1. An optical sensor assembly for measuring electrical current in a current carrying cable, comprising:
an input light polarizing element having a low Verdet constant and configured to receive an incoming light beam and produce a polarized light; a prism mounted to the input light polarizing element, the prism receiving the polarized light and having a reflective surface positioned immediately adjacent to the input light polarizing element, the reflective surface changing a direction of the polarized light passing through an intermediate portion of the prism; and an output light polarizing element coupled to the prism, wherein the prism has a high Verdet constant relative to the respective Verdet constants of the input light polarizing element and the output light polarizing element.