Zero-Power AC Current Sensor

In this study, a magnetic piezoelectric cantilever powered AC current and frequency sensor is proposed. This paper covers the configuration of the experimental setup, finite element modeling of the magnetic coupling, and the optimal spatial location of the magnetic proof mass in relation to the wire for smart grid applications. Solid and stranded copper wires of various gauges were used and carried current up to 30A. The magnets act as a proof mass to lower the frequency while also coupling to the magnetic field generated by the current carrying wire. The frequency of the AC current produces a sinusoidal force on the piezoelectric cantilever. Vibrational energy is then converted to electrical energy which can be used to power a wireless sensor node. Two different cantilevers with varying stiffness are considered as possible power/sensing elements in the proposed sensor. They are tuned to resonate at 60 Hz using neodymium (NdFeB) magnets.