Method and system for soft switching of a relay
AssigneeGeneral Electric Company
InventorsJason Creighton, David Christopher Shilling
Life of this patent
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Abstract
Provided is a system for soft switching of an electromechanical relay in a lighting control system using a sensor to detect a specified non-zero position in the electrical input waveform. Following this non-zero position, an adaptive time delay is applied before activation of the relay coil. An error detection circuit measures a time error between relay operation and the zero electrical input condition. This error signal is used to update the adaptive time delay for future relay operations. Using such a procedure has been shown to limit electrical stress on the relay, and therefore lengthen its life.
Claims12
A method for controlling a switching system configured to provide power from an alternating current (AC) power source to a load based upon operation of a relay, comprising:
- sensing, via a sensor disposed between the AC power source and the relay, a specifiable non-zero value of an AC waveform output from the power source;
- receiving, via a switching system controller, the non-zero value sensed and activating the relay at an actual switching time after a specified time delay;
- detecting, via a detector disposed between the relay and the load, changes to the voltage at the load caused by switching of the relay, searching for the specified time delay between the actual switching time and the ideal switching time which is a zero-voltage point of the AC power source;
- and
- determining a difference between the actual switching time and an ideal switching time based upon power at the load, the difference being representative of an error factor;
- wherein the controller adjusts the specified time delay in response to the error factor during future relay operation.
A switching system configured to provide power from an alternating current (AC) power source to a load based upon operation of a relay, the switching system comprising:
- a sensor disposed between the AC power source and the relay and configured to sense a specifiable non-zero value of an AC waveform output from the AC power source;
- a controller configured to (i) receive the non-zero value sensed and (ii) activate the relay at an actual switching time after a specified time delay;
- and
- a detector disposed between the relay and the load and configured to (i) detect changes to the voltage at the load caused by switching of the relay, (ii) search for the specified time delay between the actual switching time and the ideal switching time which is a zero-voltage point of the AC power source, and (iii) detect a difference between the actual switching time and an ideal switching time based upon power at the load, the difference being representative of an error factor;
- wherein the controller adjusts the specified time delay in response to the error factor during future relay operation.
Dependencies are inferred from the claim text.