A non-resonant piezoelectric sensor for measuring 50Hz or 60Hz electric currents

A non-resonant piezoelectric sensor for measuring power-frequency (50 Hz or 60 Hz) electric currents is proposed to be applied in electric power systems. The device consists of a magnetic circuit, two piezoelectric plates, and fixed plates. The magnetic circuit is made up of three NdFeB magnets and two permalloy yokes. The high sensitivity of the device is attributed to the magnetic field concentration and the induced shear stresses. A prototype has been fabricated and the feasibility of the self-powered sensor was validated. The average sensitivity reaches 28.56 mV/A in the range of 1 A to 10 A, and the accuracy is 0.02089 mV at a current of 3.5 A. A current variation of 0.02 A is distinguished under the non-resonant condition of 50 Hz. The self-powered, highly sensitive, non-resonant, and high-resolution characteristics make the device favorable for measuring real-time electric currents in electric power systems.