Designing and analyzing two non-invasive current sensors using Ampere's force law

Document Type : Article


Department of Electrical and Computer Engineering, University of Minnesota Twin Cities, Minneapolis, MN 55455, USA


Here two different non-invasive current sensors are proposed, modeled and analyzed. The current sensors are based on the Ampere Force Law (AFL), defining the magnetic force between two parallel wire carrying currents. These current sensors can be used for detecting/sensing DC and AC currents as well as their combination in a single wire or multiple wires, and they do not rely on any permanent magnets for operation. In the first configuration, there are two microbeams, in which one of them is at the vicinity of the wire and undergoes the mechanical vibrations due to magnetic force between the wire and the microbeam. The movement of the microbeam while it is generating a magnetic field induces a current inside the another microbeam, which is stationary, as the output signal of the current sensor. In the second configuration, a single composite piezoelectric microbeam is used. The magnetic force between the wire and the piezoelectric microbeam leads the piezoelectric microbeam to move, thus it produces a voltage. Both configurations present an extremely low power consumption, which is not dependent on the sensitivity of the current sensors. The dynamic response, sensitivity and power consumption of the current sensors are investigated, compared and discussed.


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