Systems and methods for determining actuation duration of a relay

摘要

An example system for determining the actuation duration of a relay can include a relay, a current-sensing device, and a controller. The relay can have an actuation coil, and armature, and a first and second contact. The current-sensing device can measure a current through the actuation coil. The controller can actuate the relay. The controller can also receive from the current-sensing device a plurality of measurement values for the current through the actuation coil. The controller can determine an actuation duration based on a local minimum value for the plurality of measurement values. The actuation duration can correspond to a duration of a movement of an armature of the relay from the first contact of the relay to the second contact of the relay. An actuation delay of the relay can be calculated based on the zero-crossing time of an input voltage value and the actuation duration.

主权项

1. A system comprising:
a relay having an actuation coil; a current-sensing device configured to measure a current through the actuation coil, the current-sensing device comprising a current sense resistor in series with the actuation coil and ground; and a controller, wherein the controller is configured to perform operations comprising:
actuating the relay,receiving from the current-sensing device a plurality of measurement values for the current through the actuation coil; anddetermining an actuation duration based on a local minimum value for the plurality of measurement values, wherein the actuation duration corresponds to a duration of a movement of an armature of the relay from a first contact of the relay to a second contact of the relay; wherein the current-sensing device further comprises a comparator circuit and a transistor, wherein the transistor is connected in series with the actuation coil and the current sense resistor; wherein the comparator circuit comprises a comparator and the current sense resistor, wherein the current sense resistor is connected by way of a diode to a capacitor and a resistor of the comparator circuit, wherein the capacitor and the resistor are connected in parallel, wherein the diode is included in an electrical path from a point between the transistor and the current sense resistor to an input of the comparator, wherein the input of the comparator is also connected to the capacitor and the resistor, wherein the controller receives the plurality of measurement values from the output of the comparator; wherein the controller is configured to actuate the relay by providing a biasing current to the transistor that is sufficient to allow current to flow from the actuation coil through the transistor and the current sense resistor to the ground.