Contactor Status Detection in Power Inverters
First Claim
1. A method of sensing an unexpected condition of an AC contactor used to couple to a power distribution system a power inverter having at least one power conductor, comprising:
- determining a voltage value for said at least one conductor;
determining a current value for said at least one conductor;
determining a phase difference using the voltage value and the current value;
monitoring a plurality of successive values of the phase difference to produce a monitoring result; and
depending on the monitoring result, determining whether or not to issue an alert signal or perform a remedial action.
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Accused Products
Abstract
A sensor-less technique is described for detecting the status of an AC contactor of a power inverter. In one embodiment, a method is provided of sensing an unexpected condition of an AC contactor used to couple to a power distribution system a power inverter having at least one power conductor. The method includes determining a voltage value for the conductor; determining a current value for the conductor; determining a phase difference using the voltage value and the current value; and monitoring successive values of the phase difference to produce a monitoring result. Depending on the monitoring result, a determination is made whether or not to issue an alert signal. Control routines embodying such technique may be stored on computer-readable media. A power inverter using such technique is described.
40 Citations
22 Claims
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1. A method of sensing an unexpected condition of an AC contactor used to couple to a power distribution system a power inverter having at least one power conductor, comprising:
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determining a voltage value for said at least one conductor; determining a current value for said at least one conductor; determining a phase difference using the voltage value and the current value; monitoring a plurality of successive values of the phase difference to produce a monitoring result; and depending on the monitoring result, determining whether or not to issue an alert signal or perform a remedial action. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A computer readable medium including program instructions for sensing an unexpected condition of an AC contactor used to couple to a power distribution system a power inverter having at least one power conductor, said instructions performing steps comprising:
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determining a voltage value for said at least one conductor; determining a current value for said at least one conductor; determining a phase difference using the voltage value and the current value; monitoring a plurality of successive values of the phase difference to produce a monitoring result; and depending on the monitoring result, determining whether or not to issue an alert signal or perform a remedial action. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A power inverter comprising:
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an arrangement of power switches; at least one power conductor coupled to the arrangement of power switches; a transformer coupled to the at least one power conductor; and an AC contactor coupled to the transformer and used to couple the power inverter to a power distribution system; a measuring device coupled to the at least one power conductor; and a controller coupled to the measuring device, and coupled to the arrangement of power switches to control switching of the power switches, wherein the controller uses measurement values from the measuring device to sense an unexpected condition of an AC contactor. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
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Specification