Alternating-Current Power Harmonic-Based Circuit State Detection

This document describes systems for and techniques of alternating-current (AC) power harmonic-based circuit state detection. In various aspects, a system includes a component, a bypass circuit for the component, and a controller with an AC power harmonic-based circuit state detector that can determine a state of the bypass circuit. The AC power harmonic-based circuit state detector may convert an AC voltage of the AC power to a direct current (DC) voltage, filter the DC voltage to obtain a voltage of a harmonic of the AC power, and compare the voltage of the harmonic to a threshold to determine that the bypass circuit is in a fault state (blown fuse). By so doing, the controller of the system can notify a user that the bypass circuit needs to be reset or replaced to reenable operation of the system and avoid poor user experience typically associated with a non- or mis-functioning system.