| US 7,521,825 B2 | ||
| Interface switch for distributed energy resources | ||
| Robert H. Lasseter, Madison, Wis. (US); and Paolo Piagi, Madison, Wis. (US) | ||
| Assigned to Wisconsin Alumni Research Foundation, Madison, Wis. (US) | ||
| Filed on Nov. 04, 2005, as Appl. No. 11/266,976. | ||
| Prior Publication US 2007/0129110 A1, Jun. 07, 2007 | ||
| Int. Cl. H01H 47/00 (2006.01); H02B 1/24 (2006.01) | ||
| U.S. Cl. 307—130 [307/126; 307/127; 307/129] | 25 Claims |
| 22. An interface switch comprising:
an internal terminal configured to connect to an internal power bus bearing an AC voltage V at a selectable frequency ω;
an external terminal configured to connect to an external power bus bearing an AC voltage Ē at a frequency ω0;
a controllable electrical switch between the internal terminal and the external terminal, the controllable electrical switch
having an open condition wherein the internal terminal is electrically isolated from the external terminal and a closed condition
wherein the internal terminal is electrically connected to the external terminal; and
a switch controller configured to control the controllable electrical switch by placing the electrical switch into the open
condition or the closed condition, wherein the switch controller is configured to identify an envelope of a waveform corresponding
to a difference between the AC voltage Ē and the AC voltage V, and further wherein the switch controller is configured to
close the controllable electrical switch at or just after a time when the envelope of the waveform of the voltage difference
between the AC voltage Ē and the AC voltage V reaches a local minimum at a point of inflection.
|