Stick-On Piezoelectromagnetic AC Current Monitoring of Circuit Breaker Panels

We present a stick-on wireless electric current monitoring system that is designed to measure and report electricity usage from circuit breaker panels in residential and commercial settings. This monitoring system uses piezoelectromagnetic (PEM) AC current sensors to couple to the magnetic fields produced by the current-carrying conductors. The PEM sensors can be easily attached to the surfaces of common circuit breaker panels, facilitating the installation by non-technical individuals. This paper describes the sensing principles and provides an analytical model of the PEM AC sensors. It also presents the architecture for a wireless current monitoring system and describes its implementation for sub-metering a circuit breaker panel in a building at the University of California, Berkeley. The theory and experimental validation of a signal deconvolution and calibration method, essential for extracting signals from cross-coupled magnetic fields, are also included.