SELF-LEARNING RELAY TURN-OFF CONTROL SYSTEM AND METHOD

摘要

An exemplary embodiment is disclosed of a relay turn-off control system for use with an alternating-current (AC) signal input. The system may include a relay, a relay current load sensor connected to the relay, and a rectifier circuit connected to the relay current load sensor and having an output. A microprocessor may be connected to the rectifier circuit output. The microprocessor may be configured to set a relay turn-off signal output time based on an empirically determined duration time for the relay to turn-off and further based on determining a zero-cross period via use of a modulo operation.

主权项

1. A relay turn-off control system for use with an alternating-current (AC) signal input, comprising:
a relay; a relay current load sensor connected to the relay; a rectifier circuit connected to the relay current load sensor and having an output; a microprocessor connected to the rectifier circuit output; and wherein the microprocessor is configured to:
a) define a plurality of successive time increments where each of the plurality of successive time increments combined are equal to a cycle time of the AC signal input;b) output a first relay turn-off signal to the relay at a first of the plurality of successive time increments;c) measure a duration time, after step b or f, for the rectifier circuit output to indicate that the relay has turned off;d) perform a modulo operation of (duration time) mod (cycle time/2), wherein a remainder of the modulo operation is one of a non-zero value and a zero value;e) store the remainder and an associated time increment in a memory coupled with the microprocessor;f) output a next relay turn-off signal to the relay at a next of the plurality of successive time increments;g) repeat steps c-f until the stored remainders of successive modulo operations transition from the non-zero value to the zero value or from the zero value to the non-zero value; andh) set a relay turn-off signal output time at the associated time increment where the remainder of successive modulo operations transitioned from the non-zero value to the zero value or from the zero value to the non-zero value.