Single-sensor microcontroller-based approach and system for ground fault circuit interrupters

Abstract

A microcontroller-based temperature compensated circuit for ground-fault circuit interrupter to meet requirements of UL 943 using a single sensor (T1) to detect both ground-fault and grounded neutral fault conditions in both full-wave (CR1) and half-wave AC power supplies as part of a ground-fault circuit breaker (10) or a receptacle device.

Description

technical field [0001] The present application relates generally to circuit protection, and more particularly to a system and method for detecting ground fault and grounded neutral conditions. Background technique [0002] To meet the requirements of UL 943, existing designs for ground fault protective devices such as circuit breakers and receptacles generally use analog circuits and two current sensors. One sensor needs to be used to detect a current imbalance that is indicative of a ground fault, a second sensor is used as part of a sleep oscillator circuit that detects grounded-neutrals that may degrade said ground fault detection capability. neutral) state. These sensors need to be highly accurate over a wide temperature range and have low part-to-part variation since the analog circuitry provides only minimal compensation or calibration capability. Also, since no non-volatile memory function is available, the analog method may not work well if the power supply is inte...

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Problems solved by technology

Also, since no non-volatile memory functionality is available, this analog method may not work well if the power supply is intermittent

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