Unbalanced current detection

Details Unbalanced current detection Unbalanced current detection

2007-04-17

2007-04-17

Zhu, John (Department: 2858)

Electricity: measuring and testing

Measuring, testing, or sensing electricity, per se

Phase comparison

C324S701000, C324S107000, C361S078000, C361S079000

Reexamination Certificate

active

11254128

ABSTRACT:
An unbalanced current detection circuit determines when a multi-phase, normally-balanced load is unbalanced. The detection circuit of the present invention includes a plurality of current-squaring circuits, each squaring a sensed current of one of the phases. A summing circuit produces a sum of the squares of the currents. If the load is balanced, this sum should be relatively constant, perhaps changing only slowly over time, with little or no ripple from that relatively constant value. In an unbalanced current condition, the sum of the current squares would consist of an average (dc) component plus a ripple (ac) component. If the amplitude of the ripple current exceeds a threshold, it is determined that the currents are unbalanced.

REFERENCES:
patent: 4423374 (1983-12-01), Hansen, Jr.
patent: 4641088 (1987-02-01), Jacobsson
patent: 4970458 (1990-11-01), Fox
patent: 5298885 (1994-03-01), McEachern et al.
patent: 5523938 (1996-06-01), Wagner et al.
patent: 5838510 (1998-11-01), Inbar
patent: 6501329 (2002-12-01), Petrofsky et al.

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